Arimaa/Elephant and Minor Piece Attacks/Illustrative Games

From Wikibooks, open books for an open world
Jump to: navigation, search

Paul Mertens vs. Toby Hudson, 2006 WC, Round 5[edit]

Gameboard | Comments

In this Arimaa 2006 World Championship game, Gold launches a crushing Elephant and Dog Attack during the early stages. By the 14th move it is already too late for Silver to stop the attack without losing material elsewhere.


37px-Arimaa board.jpg
Arimaa-border.png
Arimaa-border.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Arimaa-border.png
Arimaa-border.png
Diagram (1a) after 10s

After 10 moves, Silver appears to have the stronger attacking position, as seen in diagram (1a). The Horse on a2 is threatening a Rabbit-pull while the Silver Camel can either attempt to drag the Gold Horse from g3 to the northeast trap or displace the Horse in order to purse an Elephant and Camel Attack against the southeast trap. Meanwhile, the Gold Elephant has no immediate prospects other than a distant Horse hostage in the southwest or some Rabbit-pulling in the northwest. However, as the game played out, Silver was not able to create any strong threats before a sudden Elephant and Dog Attack against the c6 trap. Play continued in interesting fashion, 11g Dc2n Rc1n Hb3w Dc3w, as Gold decided to blockade the Silver Horse. Silver could have ignored that corner of the board and continued with an aggressive attack against the f3 trap (or played ee3s Mf3w Me3n Ee2n with a long-term camel hostage threat), but instead chose 11s ee3w ed3s mg4n Hg3n. Gold responded with 12g Rh3n Hg4s Eb5e Ec5e, which not only protected both the Gold Horse and Camel, but centralized the Elephant with some long-term threats against the Silver Camel on g5 and the Dog on d6.


37px-Arimaa board.jpg
Arimaa-border.png
Arimaa-border.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Arimaa-border.png
Arimaa-border.png
Diagram (1b) after 12g


Looking at diagram (1b), it is clear that the northwest trap is quite weak, but Silver continues with the rescue operations in the southwest quadrant, 12s ed2n Rc2e Rb2e ha2e, possibly in the hopes of pushing towards an Elephant and Horse Attack. However, Gold had a clever two-move plan in mind. It began with 13g Cd1w Db3n Ha3e Ra1n, and although the Silver Horse is no longer blockaded on b2, the Gold Horse effectively obstructed its return to b6 (the upcoming Elephant and Dog Attack could not have succeeded if the Horse were returned to b6), the Dog has moved into attack position and the Cat has occupied c1 so that Silver cannot begin an Elephant and Horse Attack without first pushing the Gold Rabbit to c3. This slow attack on c3 would be no match for Gold's threatened attack against c6. Silver could have averted disaster by unfreezing the d6 Dog and then moving it 2 steps to the west and then taking one step to the east with the Camel to avoid a potential hostage situation. However, Silver only noticed the latter threat and play continued 13s Rc2n hb2e ed3e mg5e 14g Db4n Db5n dd6n Ed5n, as shown in diagram (1c).


37px-Arimaa board.jpg
Arimaa-border.png
Arimaa-border.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Arimaa-border.png
Arimaa-border.png
Diagram (1c) after 14g


Gold has successfully launched an Elephant and Dog Attack. Normally, the Horse would be sent into the attack during the opening phase, rather than the Dog, but Gold has correctly determined that no Horse or Camel can disrupt the Elephant and Dog Attack and that the Gold Horse makes an excellent defender on the b3 square. There is no reason to attack with the Horse when a weaker piece can do the job just as effectively. Silver's upcoming loss of material is inevitable, so he had to find the best plan to minimize the damage. Ordinarily, the safest course of action would be to return the Silver Elephant to c5 so as to neutralize the Elephant and Dog Attack. Unfortunately, that defensive measure is insufficient for it would allow Gold to step the c3 Rabbit one square north and move the Camel over to c3. When defensive measure don't work, it's best to counter-attack elsewhere. The best counter-attack would distract Gold for at least 2 steps so that there would not be enough remaining steps to capture the Silver Cat. Such a counter-attack does not exist in this position. The Gold Rabbit on h4 could be dragged towards the f6 trap, and captured in 2 moves. However, Gold could respond by trapping both a Cat and a Dog in the c6 trap while Silver focused on capturing the Rabbit! Instead, Silver countered with the logical reply, 14s mh5w mg5s Hg3e mg4s, but it wasn't enough. Gold was able to capture the Cat with three steps while defending f3 with a single step: 15g Mf3n Db6n cc7s cc6x Db7e. Note that the Dog has been relocated to c7 from b6. Ordinarily that is a dangerous square for a Dog but the Silver Horses and Camel are so far away that Gold has decided that the Dog can be safely placed on c7 in order to threaten the c8 Rabbit.