The Crab Silvers (カニカニ銀 kani kani gin) is a shogi opening. It is a type of Rapid Attack Fortress opening, used mostly when playing Black (sente). It is often classified as a trap opening. It was created by professional shogi player Kōichi Kodama,[1] for which he received the prestigious Kōzō Masuda Award in 2003.
Due to the large amount of freedom of the rook to enter into the game, finding ways to attack even in the middle of a Rapid Attack Fortress has quite the merit.
Unlike the Double-Silver Rapid Attack Fortress, king and gold don't move at all from their initial position (Sitting king). In the fifth movement, rather than pushing P-66, the silver is pushed to S-77. Instead of opting not to push the rook pawn from Fortress, White (gote) will play S-33 following Black's rook pawn being pushed to P-25, which will be followed by ▲S-48, ▲P-56, ▲S-57, ▲S-46. After that, if White (gote) were to push the pawn in the 5th file, the rook will go to the center file with ▲R-58, and then, for example, ▲B-97, ▲S-66, ▲N-77, with the aim of breaking through the center.[2]
Although at first it was frequent for White (gote) to unthinkingly push the gold to △G-32, since it was difficult for Black (sente) to defend from a breakthrough from the center, making preparations beforehand by playing △G61-52 became more frequent. When aiming to attack from the center, pushing the pawn in the 3rd file with ▲P-36 allows the rival to attack the king on its weak points and also delays the attack, so it is often considered a bad move.[3]