Basic Tactics For Breaking Yagura Castle (4)

The tactic like ▲N*24 which I wrote in the previous article can be also seen in joseki.
Diag.1 is one of the Yagura Joseki called Katou Style (9-Dan Katou plays this strategy frequently.) It is the sente's variation in Yagura Silver-37 Strategy, characterized by pushing the edge pawn and ▲P-26 before advancing the silver to 46. And, the knight jumps into 25 through 17.

Diag.1

Here, gote plays △N-33 before the attack from ▲S-46 and ▲P-35. In general, the equal exchange between an attacking piece and a defending piece is good for an attacking side. But, in this case, gote has a threat with the knight in the next.
After △N-33, it proceeds with  ▲Nx+ △G32-33x (△Sx and △G43-33x are also available) ▲S-46 (Diag.2). △G32-33x means preparation for the attack from above. It doesn't look like a good shape, though.

Diag.2

In Diag.2, △N*86 is the move that gote had been aiming at since △N-33.
After ▲Px △Px (Diag.3), it looks like there is no piece to drop on 87. But, in the next, it's possible to gain a silver with △Bx46 and drop it on 87. Breaking the point in front of the king is more valuable than bishop-silver exchange. Then, promoting the rook and taking the material back can be expected in the future.

Diag.3

To remove the threat of △Bx46, sente needs to select ▲P-55 or ▲N*79 or ▲Sx.
In reply to ▲P-55, the attack with △N-85 ▲Sx86 △Nx97+ ▲Kx △P*85 (Diag.4) is effective. The silver on 86 cannot move due to the bishop's line. If ▲Lx is played instead of ▲Kx, gote will take the silver with △Bx86 ▲Bx △Rx.
Gote is better at Diag.4 because sente doesn't have a rapid attack to gote's castle yet. As you know, in the endgame, the speed to break the opponent's castle and capture the king is the most important thing.

Diag.4

▲N*79 is the same as ▲P-55. Gote will get better with the attack from △N-85.
Therefore, ▲Sx is a common move in Diag.3. After that, it proceeds with △Bx ▲Bx △Rx ▲P*87 △R-82 ▲P-35 (Diag.5). Many pro players regard Diag.5 as slightly better for gote. Thus, instead of ▲S-46 in Diag.2, ▲N*65 was played in recent pro game.

Diag.5

In this way, even if the position is still in the middle game, the tactic like △N*86 would go well depending on the situation.

Basic Tactics For Breaking Yagura Castle (3)

Continued from the previous article.
http://kingcrimsondiscipline.blogspot.jp/2014/11/basic-tactics-for-breaking-yagura_25.html

▲N*24 is a common tactic of Yagura. Then, as I mentioned earlier, there are some ways dealing with it. Let's look at the actual examples in pro games.
Diag.1 is the game between Daisuke Katagami and Eiji Iijima. It's sente (Katagami) to play.

Diag.1

Here, sente played ▲N*24. What should gote play against it?
If △G32-42 is played, ▲B*65 would be an effective attack. After the rook run to somewhere, with ▲Bx43+ △Gx ▲G*32, it's possible to make the shape for capturing the king. And, △G-31 is also the same thing with ▲B*65. Therefore, gote needs to take the knight. It proceeds with △Px ▲Px (Diag.2).

Diag.2

In Diag.2, gote has three ways to deal with the attack from above. (1) △P*23 (2) △N*31 and (3) △Sx.

(1) △P*23

As I wrote in the previous article, after ▲Px+ △Gx, the castle gets weaker against the attack from the side instead of gaining a knight. In this case, ▲B*41 becomes a fork aiming at ▲Bx23+ and ▲Bx74+. Also, if gote protects the gold on 23 with △P*24, ▲S*32 will be more severe than ▲Bx74+. Thus,  △P*23 doesn't fit into this position as there is a subsequent attack for sente.

(2) △N*31

This move adds the power to 23 in order to remove the threat of ▲S*23. But, as well as when △P*23, ▲B*41 would be a severe move aiming at ▲S*23 and ▲Bx74+. In general, the basis front of the king like ▲P24 should not be left as it is, especially while the opponent has a piece to drop on 23. It's too risky.

(3) △Sx

This is a common move. With ▲Rx △P*23, although gote loses material, he can gain a tempo instead. In the endgame, the speed to capture the opponent's king is more important than gaining material. Basically, when attacked the castle, the defender usually has two plans, continuing to defend thoroughly or countering after gaining a tempo. If it's difficult to stop the attack, the player should select the latter.

Actually, in reply to ▲Px24, Iijima (gote) selected △Sx ▲Rx △P*23. Then, it proceeded with ▲R-27 △N*85 (Diag.3). ▲R-27 means protecting the point on 77 horizontally, and △N*85 added more power to 77.

In Diag.3, ▲S*41 is considered as one of candidate moves. This is also the basic tactic for breaking Yagura. If the gold run to 42, there would be an attack like ▲S*52 △G43-33 ▲B*51.
Katagami played ▲S*65 defensively, though. It would be still an equal game in both cases.

Diag.3

Compared with △P*23 and △N*31, △Sx appears frequently against the attack from ▲N*24.

International Shogi Forum

The 6th International Shogi Forum starts today in Shizuoka City, Japan. This event is organized by Shogi Association once every 3 years, and, this year, 46 players from 38 different countries are supposed to participate in it. I'm just heading there now. There is an evening party today. The tournament will be held for 2 days from tommorow. Besides the tournament, there are other programs, such as exhibition game by pro, instruction game by pro, including me, and chess match between Yoshiharu Habu and GM Peter Heine Nielsen. I'm so excited to join it!