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The 2010 Arimaa World Computer Championship began on 1 March 2010 with a field of eight bots. Marwin, a first-time entrant in the tournament, performed very well in the qualification round and earned the top seed. Despite a huge rating advantage, the Arimaa community is uncertain whether marwin will be strong enough to overthrow defending champion and #2 seed, clueless. A veteran field of developers round out the field with GnoBot, OpFor, sharp, Badger and five-time champion Bomb all in the hunt for a top three position. The wild card of the tournament is the #8 seed pragmatictheory, developed by Martin Priotte and Martin Chabbert who were part of the winning 2009 Netflix Challenge team.

• For tournament rules, information and qualifying round summary see Official Tournament Rules and Information.
• Also see 2010 World Computer Championship Rules

For other events see Event Reports

Contents 1 Entrants 2 Round 1 2.1 bot_pragmatictheory vs. bot_marwin 2.2 bot_GnoBot vs. bot_Badger 2.3 bot_sharp vs. bot_OpFor 2.4 bot_clueless vs. bot_Bomb2005CC 3 Round 2 3.1 bot_OpFor vs. bot_marwin 3.2 bot_sharp vs. bot_pragmatictheory 3.3 bot_Badger vs. bot_Bomb2005CC 3.4 bot_clueless vs. bot_GnoBot 4 Round 3 4.1 bot_Bomb2005CC vs. bot_pragmatictheory 4.2 bot_Badger vs. bot_OpFor 4.3 bot_marwin vs. bot_clueless 4.4 bot_GnoBot vs. bot_sharp 5 Round 4 5.1 bot_sharp vs bot_Badger 5.2 bot_OpFor vs bot_Bomb 5.3 bot_marwin vs bot_GnoBot 6 Round 5 6.1 bot_OpFor vs bot_clueless 6.2 bot_marwin vs bot_sharp 7 Round 6 7.1 bot_marwin vs bot_OpFor 7.2 bot_clueless vs bot_sharp 8 Round 7 8.1 bot_clueless vs bot_marwin 9 Round 8 9.1 bot_marwin vs bot_clueless 10 Round 9 10.1 bot_clueless vs bot_marwin 11 Round 10 11.1 bot_marwin vs bot_clueless 12 Results

Entrants

• CCh W-L = Cumulative Win-Loss record in all previous Championships [# of previous tournaments]
• 1st, 2nd, 3rd = Number of all-time 1st, 2nd and 3rd place finishes

Seed	Bot Name	Developer	CCh W-L	1st	2nd	3rd
1	marwin	Mattias Hultgren (tize)
2	clueless	Jeff Bacher (jdb)	20-11 [5]	1	2	1
3	GnoBot	Toby Hudson (99of9)	7-17 [5]		1	2
4	OpFor	Brian Haskin (Janzert)	6-6 [2]			2
5	sharp	David Wu (lightvector)	5-6 [2]		1
6	Badger	Paul Pogonyshev (doublep)	3-3 [1]
7	Bomb	David Fotland (fotland)	30-6 [6]	5
8	pragmatictheory	Martin Piotte & Martin Chabbert

Round 1

bot_pragmatictheory vs. bot_marwin

Marwin completely dominated the game after a quick horse frame on move 6s followed by a cat capture on 10s. Once the silver elephant rotated out of the eastern frame and froze the gold camel on turn 14, the game was effectively decided. After several more captures a silver rabbit scored down the h-file on turn 27.

bot_GnoBot vs. bot_Badger

GnoBot took a commanding lead on move 5s with a silver camel hostage fork at e3. Rather than accept a horse for camel exchange, Badger took the f2 cat instead. Already in a big hole, Bader’s silver horse was threatened on 12s and it tried numerous tactical tricks to save the piece but to no avail. After a brief struggle, GnoBot emerged with another cat and horse to pad its lead. Silver made a slight comeback with a dog capture on 20s but Gold immediately re-applied the pressure by threatening a dog in the f6 trap and advancing a rabbit to f7 on 22g. Another complex tactical exchange ensued but Gold’s advanced rabbit and extra pieces made the final result inevitable. With most of the strong silver pieces in the south, and a wall of silver rabbits being the only real defenders, a gold rabbit reached the 8th rank fairly easily on turn 30.

bot_sharp vs. bot_OpFor

Sharp grabbed the early lead with a cat capture on the 14th turn. OpFor likely didn’t attempt to save its cat due to the risk inherent in 13s hg6s hg5s hg4s de7e 14g Hf3n Ed5e Ee5s Ee4s. After creating dual dog threats on 22g, sharp was ahead by 2 pieces after 23 turns. OpFor made a nice 25s move to restrict the gold elephant’s mobility (Diagram 1a). Had that been followed up with a strong camel + horse attack against the f3 trap OpFor would have had a fair bit of compensation for its 2 lost pieces. However, OpFor let its opponent off the hook too easily on the 29th turn and sharp again built a powerful position. But OpFor was miraculously saved on the 34th move when sharp sent an illegal move, ending the game on the spot.

bot_clueless vs. bot_Bomb2005CC

Clueless transposed a dog threat on 5g into a very quick rabbit capture on move 9 because Bomb failed to use its elephant rather than the h7 rabbit to unfreeze the dog on 5s. Clueless continued to push small silver pieces into southeast quadrant but it failed to capitalize on a potentially strong cat flip to f3 on 14g. After a later horse trade, clueless extended its material lead with a cat capture on 29g. Bomb inexplicably sacrificed a rabbit on 31s and then clueless saved its own endangered rabbit on 33g to maintain a dominant three-piece advantage. A 5-piece exchange soon followed so that after 39 turns clueless held a 13-9 advantage in number of pieces. Another series of trades left Bomb with a pair of deputies by turn 47 but Bomb’s 3 extra rabbits were too much to handle. Clueless found a forced goal in three in just 4 seconds on move 50g to clinch the win.

Round 2

bot_OpFor vs. bot_marwin

OpFor dug itself into a huge hole early by leaving its elephant on f7 on 5g and then later placing greater importance on preventing a camel hostage than an elephant blockade. The gold elephant actually could have broken free on 10g but OpFor wasn’t willing to concede a horse frame on 10s. But instead the gold elephant dug itself in deeper, getting blockaded at f8 on the 11th turn. Marwin easily dominated the rest of the game, first by taking a gold horse hostage at b7 on 15s. The gold camel was then taken on 19s and marwin had no difficulty winning building upon its advantage with the two strongest free pieces. But marwin was far too passive with its silver rabbits and so OpFor survived until move 41, eventually losing by immobilization rather than by goal.

bot_sharp vs. bot_pragmatictheory

Sharp opened the game with an incredibly dangerous-looking elephant advance to b7 on 4g. However, 4s ed6w ec6w cf6w ce6w wouldn’t have been an effective blockade due to the passive position of all the strongest silver pieces and the resulting gold counter-threats. It seemed that Sharp could have gained an early lead with a rabbit pull down the b-file but it played too slowly and it was pragmatictheory that gained the upper hand with a strong elephant + horse attack on 9s. That advantage was squandered away on 10s with an illogical horse move and the piece was therafter taken hostage at f1 by the gold camel. Sharp took the material lead with a silver rabbit capture on 21g. The silver camel was taken hostage on move 24g and hostages on both wings led to a second silver rabbit capture on 29g. Pragmatictheory put up a strong tactical fight in the difficult position but its position declined rapidly after losing a silver cat in the c6 trap on turn 35. Sharp made a long-term gambit on the 37th move giving up a dog for cat but gaining a firmer grip over its 2 southern traps in the process. After taking the silver camel, sharp ploughed ahead with its rabbits and scored the goal on 46g.

bot_Badger vs. bot_Bomb2005CC

Despite two silver horse on the east side, Badger gained a rapid advantage by attacking with elephant + horse at the f6 trap and then winning a silver rabbit on 7g. By 9g both horses had reached the 6th rank on opposite sides though the b6 horse was dangerously near the c7 silver camel. The two sides traded horses on 15s and 16g while Gold’s positional advantage remained strong. Bomb nicely rotated its elephant away from the western dog hostage on 19s to get its position more active again. But Badger took advantage of weak western silver rabbits to triple its material advantage on turns 23 & 24. Badger correctly followed up its huge material lead with more aggressive play but it made a big mistake on the 27th turn by allowing a silver rabbit to advance to b4. But correct defensive tactics allowed a gold cat to stop the rabbit and Gold went back on the attack. Badger nonchalantly captured another cat and rabbit, extending its material lead to five pieces, even as Bomb was desperately trying to build a goal attack in the southwest. But the Bomb could not find a path to victory and Badger scored on the barren eastern side on 37g.

bot_clueless vs. bot_GnoBot

This game was repeatedly delayed by technical problems, but eventually the game was successfully re-started. GnoBot had the better position after 11 moves due to the passive position of the gold elephant but it didn’t a launch a beneficial swarming attack against the c3 trap. Instead, the two bots just pushed and pulled each other’s pieces for 20 moves before Silver needlessly abandoned a silver rabbit on turn 31. Clueless padded its lead on 43g with a cat capture but GnoBot immediately retaliated with a cat frame and high camel hostage. The camel was freed on turn 50 which led to a strong gold attack against the c6 trap. Unable to successfully defend its home trap, GnoBot sacrificed a cat and dog on moves 54 & 55 to delay the goal threat from the b6 gold rabbit. Clueless followed that with another rabbit capture on 57g before the silver elephant was finally able to stop the bleeding in the northwest. Without the silver elephant’s protection, the southern silver horse was removed on turn 59, leaving Gold ahead by 6 pieces. GnoBot did later capture one gold horse before succumbing to defeat on 73g.

Round 3

bot_Bomb2005CC vs. bot_pragmatictheory

In the opening while developing its pieces, Pragmatictheory allowed a dog to get flipped down and framed on F3. It then tried to relieve the frame with its camel. But by move 10 the camel had been taken hostage and the frame reestablished with the silver elephant ending up on F2. Pragmatictheory then broke the frame with a horse coming to D3. But this allowed Bomb to block the silver elephant on F2 and attack freely with its camel in the west. Bomb then pulled a horse down toward C3, but Pragmatictheory was able to defend and evade using a rabbit and dog until move 17. Bomb finally was able to block silver from bringing any more defenders to C3 and was able to capture a horse. This did allow silver to get the elephant back out to E3, then on move 18 flip the gold camel over to F3. On move 19 and 20 Bomb then started attacking F6 using both of its Horses. Pragmatictheory was once again fairly adept at defending the trap using small pieces. On move 22g Bomb brought its camel up from F2 to F4 to help with the attack on the F6 trap. Pragmatictheory prevented the camel from developing further by pulling it over and freezing it on E4. Bomb brought the horse back from E6 to unfreeze the camel and push west to threaten the silver horse on D3. Silver temporarily saved its horse by pushing south to D2, but also brought the silver dog back to F4. This allowed gold to frame the dog for the 3rd time of the game on move 24. During the rest of the 20s gold was able to setup a camel-horse attack against C6 while silver was unable to make any progress. Then starting on move 30 gold was able to make a series of captures of 3 rabbits and a cat. This left no pieces and only 3 silver rabbits above the 6th rank to defend against goal. On move 33 Pragmatictheory brought its remaining horse back to try and defend, but Bomb was able to quickly goal on move 36.

bot_Badger vs. bot_OpFor

Badger’s gold camel found itself in a hostage fork as early as move 4s but it was kept alive by the gold elephant. With the two strongest gold pieces tangled in the north, OpFor quickly initiated a silver horse attack against f3. It appeared on turn 11 that Badger would win a dog for cat trade but it actually gave up both of its cats for free in a futile bid to save its d7 hostage camel. On 17s OpFor sacrificed a dog for rabbit plus a guarantee to win additional material from the dual hostages in the north. A gold rabbit was taken on 24s, extending OpFor’s piece lead to 15-11 including the capture of the gold camel. After two more pieces were removed from each side, OpFor used a pair of advanced rabbits to force goal-in-three starting with 29s.

bot_marwin vs. bot_clueless

Clueless built an early advantage by pushing a hapless gold cat offside on 6s. Marwin offered to exchange the cat plus a gold horse in return for the silver camel; Clueless took the cat but turned down the rest of the deal. Eventually the silver camel was taken hostage at g2 while both gold horses ventured north to fight for Silver’s traps. Clueless captured a second gold piece on 16s but Marwin had the camel hostage plus a pair of horses on e6 and g6 on turn 17 for decent compensation. It seemed that the silver elephant could push a horse to d6 on 19s, which would have simultaneously threatened both gold horses, but instead Clueless advanced a horse and rabbit towards the southwest. Marwin demonstrated the folly of that strategy by transferring its camel to c3 on 22g. After taking two strong silver hostages Marwin had some excellent prospects but Clueless survived the ensuing three-for-three piece exchange and after 29 moves Silver had a 13-11 piece lead, having taken a gold horse + 2 rabbits in exchange for the silver camel. The bots traded dogs on 31s and 32g but the most prominent positional feature on the board on 32s was the frozen gold camel at d4. If Clueless could capture that piece it would virtually decide the game, but it didn’t foresee any such opportunity and chose to preserve the framed rabbit with its elephant instead. Of the 22 pieces still on the board, 14 were rabbits which meant that the endgame was certain to be sharp and exciting. After 37s there were 3 silver rabbits in the southwest quadrant but Marwin captured them all by turn 42 in return for the gold dog. The material position was close (extra gold camel + rabbit for silver horse + dog) but the gold elephant was poised to capture the g4 silver rabbit. In order to save the rabbit, Clueless first employed a capture threat as a delaying tactic on 42s (Diagram 3a) but Marwin turned up the heat with an apparently premature -- based upon the outcome -- rabbit advance along the a-file. Clueless out-manoeuvred Marwin in the ensuing struggle and the gold elephant had to rescue the gold camel before the g4 silver rabbit could be taken. After a clever blockade of the b7 square on 48s, and with the two strongest gold pieces far away from the action, Clueless quickly dominated the board with rabbit threats on each wing supported by the horse and dog. It found the winning goal-in-three on 49s, again needing just 4 seconds to do so. With its 3rd straight victory, Clueless has earned a bye in round three. Marwin took its first loss but it has already proven a worthy adversary for the defending computer champion and will no doubt get at least one more shot at redemption.

bot_GnoBot vs. bot_sharp

While Sharp was content with just a rabbit pull in the opening, GnoBot charged ahead for an early elephant + camel attack at f6. Sharp won an early dog for cat exchange and then extended the lead with a rabbit capture on 17s. GnoBot was almost able to obtain a powerful frame at f6 on 22g but sharp had already foreseen and prevented that idea by positioning its pieces for a potential goal-in-one if the gold horse tried to push its way to e6 via e5. But GnoBot did win a dog + rabbit for cat + rabbit exchange, narrowing the deficit to just a gold rabbit after 24 turns and then it tied up the game on 27g in a wide-open board. A silver rabbit was framed at c6 on 30g (Diagram 3b) but Sharp was more focused on a rabbit advancement strategy at this stage. Sharp then sacrificed its c6 rabbit to advance another rabbit to e3 and then created a second rabbit threat at h4 on 32s. It wasn’t possible to stop both rabbits and a silver rabbit reached the goal on turn 33.

Round 4

All three games in round 4 will match a 2-1 bot against a 1-2 opponent. So there could be anywhere between four and seven surviving bots in round 5.

bot_sharp vs bot_Badger

Sharp took the early positional lead when it dragged the silver camel down to e4 on move 5g. With the silver elephant poorly positioned at g4, Badger should have conceded a camel for horse exchange, but it tried to keep its camel alive instead. That strategy cost Badger dearly and it was down a camel and a dog for no compensation after just 10 turns. Badger won a gold horse on 13s but Sharp retaliated with a very strong horse frame on the next turn. Sharp released the horse frame on 16g to push an exposed silver cat into the f3 trap. Despite the material disadvantage, Badger held out for a long time until a gold rabbit found a path through the depleted silver defence on 32g. Sharp is now 3-1 and it actually had a winning position in its first game until an illegal move resulted in its only loss to date. Badger is eliminated with a 1-3 record.

bot_OpFor vs bot_Bomb

The opening sequence featured a prolonged chase between the gold camel and the silver horse, with the silver elephant continually running interference on its ally’s behalf. Bomb framed a gold cat on its c3 home trap on 13s but the position was double-edged due to a strong gold attack in the northeast. The framed gold cat was erased in return for a silver rabbit and then Bomb set up a new threat against a gold horse on 16s. OpFor continued its own attack winning another silver rabbit and a cat in return for the horse. OpFor took a silver horse on 19s and the northeast quadrant was so heavily depleted that the outcome was no longer in doubt. A gold rabbit reached the 8th rank on move 22g. OpFor improves to 3-1 while Bomb is eliminated with its glory days behind it (unless David Fotland is ever inspired to fix its glaring weaknesses, of course).

bot_marwin vs bot_GnoBot

Marwin took the early material lead when the silver elephant abandoned a framed rabbit on 9s to push the gold camel offside. Down by a rabbit, and with another hanging at a3 after 15 turns, GnoBot’s hopes lay in a potential camel fork in the middle of the board. But the camel soon escaped to safety on the east side and the second rabbit was removed on 24g. A third silver rabbit was soon captured but then on the 33rd turn GnoBot managed to win a horse for a rabbit trade. But four rabbits are certainly worth more than a horse and Marwin still held a solid position. The bots made a two-for-two trade involving a camel and cat from each side between moves 36-38, greatly benefiting Marwin due to its numerous and advanced rabbits. Marwin quickly found a goal-in-two on its 40th move. Marwin has been dominant against all bots other than Clueless and it now sits at 3-1. GnoBot had its best year ever in 2009 with a 2nd place finish but it is eliminated with a 1-3 record this time around.

Round 5

All of the 1-2 bots lost in round four so there are only 4 bots remaining. No bots can be eliminated this round and, in fact, the round 6 pairings are already known regardless of the outcome of these two games.

bot_OpFor vs bot_clueless

The opening sequence was a bit bizarre as the gold elephant repeatedly pulled silver pieces over and over again, even though most were innocuous and reversible. OpFor continued its pulling strategy with its elephant deep into silver territory until the elephant suddenly found itself enclosed on all sides after 23 turns. A gold rabbit was lost on 26g but the gold pieces continued their fight to rescue the elephant from its northern prison. However, both the silver elephant and silver camel were participating in the elephant blockade and so the gold camel was the strongest free piece. OpFor made efficient use of this piece, winning a silver horse and taking the material lead on 33g. A silver rabbit was taken on 34g and Gold would have had a big lead except for the fact that the strongest free piece was no longer the gold camel: Clueless had rotated its elephant out of the blockade on 34s and it was heading straight for the strongest gold pieces.

The silver elephant captured a gold horse but OpFor responded with a silver cat capture, leaving it ahead by a cat despite its hopeless position. The gold horse helped to free the elephant from the blockade with a rabbit pull on 41g. Had the elephant actually bothered to escape, OpFor would have had the stronger position due to a better coordination of pieces and the vulnerable c4 silver rabbit (Diagram 5a). Instead it tried to rescue a cat with its camel, allowing Clueless to seize control of the board despite a one rabbit deficit. OpFor advanced a rabbit up the barren g-file on 47g, ordinarily a good strategy given the gaping holes in the silver position, but it didn’t work in this instance. Clueless took two gold rabbits to regain the material lead on 50s for the first time since the 33rd turn. OpFor continued to charge ahead with its rabbits throughout the endgame but one rabbit after another was cut down by the silver defenders. Finally, the gold dog had to abandon the last advanced gold rabbit on 67g to freeze the g7 silver rabbit. But Clueless had other rabbits in reserve and only 2 gold rabbits and a gold cat could not hold off multiple threats for long. A silver rabbit reached the goal line on 69s, giving Clueless a perfect 4-0 record.

bot_marwin vs bot_sharp

The silver elephant continually pushed gold pieces offside in the opening: a gold horse to g5 on 7s, a dog to e5 on 9s and a cat to e5 on 10s. But all that to no avail as Marwin established a strong elephant + horse attack at f6 while finding a way to bring the cat and dog to safety on the east side. Sharp made a tactical error on 15s by leaving the silver horse exposed to the gold camel and it led to a horse for cat trade in Marwin’s favour. An unusual gold horse for silver dog + rabbit exchange followed on turns 19 & 20, maintaining a strong material lead for Gold. But Sharp made a strong series of moves soon thereafter, including a nice rabbit advance to c4 on 22s. A rabbit trade on 23s and 24g followed by a silver cat advance to b3 on 24s applied the pressure to gold’s position but also left a gaping hole in the north half of the board should a gold rabbit ever find its way up there. Pushing the rabbit onto the trap, rather than to the a3 square on 24s (Diagram 5b) would have been stronger because that gold rabbit easily advanced to a6 on 25g. Nevertheless, Sharp did hunt down the rabbit with a cat, removing it on 27s followed by a gold capture on 28g. Marwin was now ahead by one dog. Sharp made a poor decision to trade rabbits on 31s as that ceded control of the c6 trap to Gold. Marwin found the correct winning idea on 33g, charging straight north with the a2 rabbit into silver’s weak northwest quadrant. Marwin improves to 4-1 after beating this much-improved version of Sharp.

Round 6

bot_marwin vs bot_OpFor

The opening sequence featured a pair of strong attacks: a gold elephant + horse attack against the northeast quadrant versus a silver elephant + camel attack in the southeast. Gold’s attack appeared to be faltering after 13s due to an e7 hostage horse and a misplaced elephant but in reality it was Silver that got into difficulty first. OpFor withdrew its camel to safety on 15s and Marwin reclaimed its f3 trap and captured a rabbit on 19g. Further difficulties for OpFor led to the loss of the silver camel and it passed up the opportunity to capture a gold horse in return on 23s. The gold elephant protected the f6 trap to save the horse on the next turn and Marwin soon created new threats on the western front. A cat for rabbit trade soon followed and Marwin was ahead by roughly a camel, with a 14-13 piece lead. Another silver rabbit was taken on 31g to extend Gold’s lead to a camel & cat. The silver elephant held both gold horses hostage after the 32nd turn but that was of no help due to the passively placed silver elephant and the dominant eastern gold camel. Marwin slowly whittled away the silver rabbits, capturing 4 more of them without any gold losses between turns 34-43. With plenty of open territory to advance, a gold rabbit raced ahead and scored on 46g. OpFor is eliminated but will still claim the 3rd-place prize if Clueless can defeat Sharp.

bot_clueless vs bot_sharp

The opening sequence featured a pair of strong attacks: a gold elephant + horse attack against the northeast quadrant versus a silver elephant + camel attack in the southeast. Gold’s attack appeared to be faltering after 13s due to an e7 hostage horse and a misplaced elephant but in reality it was Silver that got into difficulty first. OpFor withdrew its camel to safety on 15s and Marwin reclaimed its f3 trap and captured a rabbit on 19g. Further difficulties for OpFor led to the loss of the silver camel and it passed up the opportunity to capture a gold horse in return on 23s. The gold elephant protected the f6 trap to save the horse on the next turn and Marwin soon created new threats on the western front. A cat for rabbit trade soon followed and Marwin was ahead by roughly a camel, with a 14-13 piece lead. Another silver rabbit was taken on 31g to extend Gold’s lead to a camel & cat. The silver elephant held both gold horses hostage after the 32nd turn but that was of no help due to the passively placed silver elephant and the dominant eastern gold camel. Marwin slowly whittled away the silver rabbits, capturing 4 more of them without any gold losses between turns 34-43. With plenty of open territory to advance, a gold rabbit raced ahead and scored on 46g. OpFor is eliminated but will still claim the 3rd-place prize if Clueless can defeat Sharp.

Round 7

bot_clueless vs bot_marwin

A silver camel was threatened in the opening and that prompted Marwin to send in a powerful rescue squad: after 11 turn the 4 strongest silver pieces were all in the southern half while only a single gold dog stood in the north half. But Clueless held its ground, fighting off the silver invaders and obtaining a horse hostage on 15g. Marwin took advantage of the poorly placed gold dog on 15s, forking it at d6 but the real consequence of the move was a rabbit for cat trade offer. Clueless accepted the offer before the removal of silver horse hostage for gold dog hostage on the 18th turn. So each side had captured two pieces but Gold was ahead by the narrow margin of horse & rabbit for cat & dog. The next struggle involved a positional battle between the gold camel, which wanted to dislodge the silver horse from the 3rd row, and the silver elephant that wanted to threaten the gold dog while keeping its horse safe. The situation was resolved on the 26s when the silver horse took shelter at c2 but Clueless padded its material lead with a rabbit capture on 27g while establishing a strong dog at the f7 square. The gold camel charged ahead on 28g to help the dog control the f6 trap; curiously, Clueless chose the dangerous e6 square rather than the safer f5 one for its camel. If it wanted to provoke an exchange, it got its wish: Marwin was willing to trade its c2 silver horse for the exposed gold camel. The material position was now completely unbalanced: a gold camel, dog and cat had been traded for two silver horses and two rabbits. Another gold attacker advanced up the e-file on 32g but this time Marwin was able to temporarily ignore the gold horse thanks to a silver rabbit advance along the nearly-empty h-file (only the h1 gold rabbit stood in the way). A gold cat blocked that rabbit’s path but suddenly a second silver rabbit created a goal-in-one threat via c3 on 33s (Diagram 7a). The gold horse had to abandon its northern ambitions to stop the silver rabbit but on the following move 35g, the gold cat was able to capture the eastern silver rabbit. With 8 gold rabbits still on the board versus 5 for silver, plus the removal of both silver horses, Clueless had certainly amassed enough material to compensate for its lost camel and to have better prospect in the endgame. Also, the “deputy” silver camel was a complete non-factor on the b1 square. Clueless offered a two-for-two rabbit exchange on 36g but Marwin correctly declined the offer, already behind in the rabbit count. A shocking miscalculation by Clueless to blockade the silver elephant on 39g briefly allowed Marwin to seize the initiative with a rabbit advance in the east but the gold defenders quickly returned to strong positions to maintain Gold’s advantage. The silver elephant jumped back into the action on 41s and it seemed that 42s Df2n ee2e Rf4w Df3x df5w would give Silver good scoring chances. Instead, the elephant went after the gold horse in the north. But by the time that piece was captured Gold had once again taken control of the board and generated threats on both wings. Move 48g sealed the deal as Silver no longer had the resources to hold back gold rabbits on the two sides. Clueless pushed ahead with dual threats and a goal was scored on 52g. These two bots have now played two exciting and dramatic games but after two losses Marwin will now need three consecutive victories. Clueless is one win away from becoming a repeat champion.

Round 8

bot_marwin vs bot_clueless

Marwin attacked early but overextended his position too early and the Gold army was in a fair bit of difficulty early. Clueless capitalized by framing a gold cat on 8s and then removing it from the board on the next turn. The two sides exchanged horses and then Clueless took the gold camel hostage on 18s. But the hostage situation was short-lived because Marwin exploited an advanced silver horse to generate counter-chances in the south. When the silver elephant left the f6 trap to help the horse survive, it left Gold with a strong camel in the northeast. The position got a bit wild when Marwin abandoned its horse and dog so that the elephant could pursue the gold camel and dog on 26s (Diagram 8a). Each bot captured an opposing dog in the melee and the gold camel fled to the d8 square. The position calmed down a bit after a silver rabbit was framed on the c3 square on 32g. With both elephants tied down to the c3 trap, the gold camel became active once again and Clueless responded with the initial steps of a general rabbit advance. The silver elephant abandoned the framed rabbit (leaving the material position almost even with 13 pieces remaining on each side) and Marwin set up a potential horse exchange on turn 38 but Clueless had to avoid the trade which would have left its pieces in complete disarray. But when the position stabilized once again, it was Marwin that emerged with the much stronger position: the silver horse was taken hostage on 42g and the eastern silver rabbits were exposed to danger. Clueless tried to prevent material loss by advancing its camel to f4 but the gold elephant returned to the southeast and two silver rabbits were quickly taken. Yet another complex tactical exchange followed in which Clueless tried to generate counter-threats in the face of an endangered camel. Marwin won the silver camel in return for a gold dog & rabbit and then a gold rabbit advanced to f4 on 53g to apply greater pressure to the silver defence. That rabbit indirectly protected the other gold pieces due to the long-term goal threats and it eventually forced the silver elephant back to g6 on 57s. The tension had been broken and Clueless had nothing left to fight against the gold assault after a cat capture on 58g. Marwin found a very creative goal-in-three on 59g, threatening goal-in-one on the f-file but also taking one step closer to c8 with the elephant so that a later gold rabbit advance to a8 would be inevitable. Marwin has forced a 9th round game but Clueless can still claim the championship with just one more victory.

Round 9

bot_clueless vs bot_marwin

Clueless gained an early positional advantage with a secure high silver horse hostage at g4 on move 5s. Marwin ran its elephant underneath the f3 trap to attempt a disruption of the hostage situation but Clueless defended against it. Clueless’ advantage slipped away when a gold dog was frozen at e5 on 10s. But Clueless played aggressively to try to regain the advantage, using an elephant + camel attack in the east and advancing the western gold horse into the north. But the gold army was overextended and the gold camel was taken hostage on 16s and the western gold horse was frozen by the silver camel on 19s. Because of the phalanx that prevented the gold elephant from reaching d6, Marwin was able to convert the dual threats into a horse for rabbit exchange and then it made use of its material advantage thereafter to establish strong silver horses beside both southern traps. With all 4 traps secured, a silver rabbit made a strong march south on 28s. It was impossible to force a rabbit through against many gold defenders but the introduction of second rabbit threat in the west overloaded the gold defenders. A gold cat was captured on move 37s but Marwin had to delay its own goal attacks when Clueless created a pair of goal-in-one threats on 38g and 40g. But once those gold attacks were easily halted, the silver rabbits resumed their advances and a goal was scored on 43s. Each bot now has 2 losses and for the first time since the introduction of the Triple-Elimination format, there will be a winner-take-all deciding game!

Round 10

bot_marwin vs bot_clueless

Clueless had a strong position after just 4 turns, obtaining an elephant + horse attack against the c3 trap but it didn’t know how to proceed and settled for a horse trade on the 11th turn. Next it was Marwin that built a strong attack, using an elephant + dog in the northwest which was quite strong due to silver’s weakened western flank. Marwin attempted to win a silver rabbit in the c3 trap, but when the silver elephant intervened it led to an exchange of cats on 19s and 20g. The gold pieces worked together for an effective a3 silver rabbit hostage and so Marwin tried to work towards a second rabbit hostage on the eastern side. Clueless tried to use its camel to hold the eastern threats, but it had to run to the west on 27s to avoid the gold elephant. The exposed silver rabbit was taken and then the position became razor-sharp after 29 turns with both sides using elephant + camel attacks on opposite diagonals. By the 33rd Marwin had extended its material advantage by capturing 2 silver rabbits in return for the last gold cat. But Clueless still had good chances thanks to its advanced rabbits in the southwest quadrant. Marwin wisely gave back some material to slow down the silver attacks and after 36 turns (Diagram 10a) Gold had a small but significant material advantage and Silver’s goal prospects had diminished considerably. Because of the powerful gold camel on g6 and the open territory for gold rabbit advances in the east, Marwin built an enormous positional advantage by the 40th move. The powerful goal attack was converted into the win of a silver horse on 42g. The silver elephant finally rotated away from the c3 frame on 42s but Clueless was never able to salvage the busted position. The silver elephant was able to prevent the eastern gold rabbit from scoring and it achieve a gold dog for silver rabbit trade. There was a rabbit exchange on the 48th turn which left Clueless with only 2 rabbits versus 5 for Marwin. One of the silver rabbits was removed on 52s and the last one was threatened on 54s which would have been an instant victory. A silver cat unfroze the silver rabbit to protect it, but once the cat was itself taken there was nothing left to prevent a gold rabbit from scoring in the east. Marwin scored the victory on 58g and clinched an incredibly exciting three-game comeback in rounds 8-10.

Results

Seed	Participant	Rd. 1	Rd. 2	Rd. 3	Rd. 4	Rd. 5	Rd. 6	Rd. 7	Rd. 8	Rd. 9	Rd. 10	W-L	Finish
1	marwin	S 8 W	S 4 W	G 2 L	G 3 W	G 5 W	G 4 W	S 2 L	G 2 W	S 2 W	G 2 W	8-2	1st
2	clueless	G 7 W	G 3 W	S 1 W	bye	S 4 W	G 5 W	G 1 W	S 1 L	G 1 L	S 1 L	6-3	2nd
3	GnoBot	G 6 W	S 2 L	G 5 L	S 1 L							1-3	t-5th
4	OpFor	S 5 W	G 1 L	S 6 W	G 7 W	G 2 L	S 1 L					3-3	3rd
5	sharp	G 4 L	G 8 W	S 3 W	G 6 W	S 1 L	S 2 L					3-3	4th
6	Badger	S 3 L	G 7 W	G 4 L	S 5 L							1-3	t-5th
7	Bomb	S 2 L	S 6 L	G 8 W	S 4 L							1-3	t-5th
8	pragmatictheory	G 1 L	S 5 L	S 7 L								0-3	8th