Side Pawn Capture

In this opening, this pawn is captured by an opponent's rook in a gambit move – typically, made by Black with Rx34.

The move has the typical characteristics of gambits: Black gains material with the extra pawn but now has lost tempo as their rook is now off its original file and requires a few moves to maneuver the rook back to the second file safely, White has lost material but now has faster development including the possibility of dropping a pawn to attack on the third file later (and Black has no comparable extra pawn drop possibilities).

The Side Pawn Capture idea is very old with records showing it was played already during the Edo period.

Nevertheless, in between the Meiji period and the beginning of the Shōwa period (1868–1930), capturing the pawn on 34 was considered a bad move for Black, and hence the old shogi proverb “Side pawn capture means three years of trouble.” In particular, it was thought at the time that although the capture was profitable in that a pawn was acquired, for Black it meant that the buildup of the formation would be slowed down, making it a bad idea.

Shogi master (and eventual Lifetime Meijin) Yoshio Kimura would challenge this prevailing view by obtaining a very high winning record playing Side Pawn Capture, and soon the strategy became popular for Black.

Other top shogi players to adopt Side Pawn Capture were Kunio Yonenaga, Makoto Nakahara, and Kōji Tanigawa.

Exceptional developments in the Side Pawn Capture opening occurred by the end of the 1980s.

With the appearance in the shogi world of top players like Yoshiharu Habu, Toshiyuki Moriuchi, and Yasumitsu Satō (often called the Habu generation), investigation into the opening and subsequent middlegame strategies rapidly developed.

In 1997, Makoto Chūza first demonstrated the R-85 variation, which brought a novel interruption in Side Pawn Capture theory.

Since pulling White's rook back to the fifth rank (R-85) countered the up-to-then conventional strategy, professional shogi players had a lot of trouble accommodating it due to the shogi sense they had accumulated since they were children, and for a while the winning rate for White went unusually up to almost 70%.

With further research into this strategy, Tadahisa Maruyama adopted successfully Side Pawn Capture when playing White in his A-class ranking matches to become a Meijin challenger in 1999 and 2000, even using the same strategy when playing White in his Meijin match.

The Side Pawn opening is typically started with both players attacking each other's bishop (although transpositions with later moves are possible).

Furthermore, this board configuration gives a strong indication of the Side Pawn opening.

However, a Double Wing Attack opening is still possible depending on whether either player actually takes the side pawn in the subsequent moves.

The Side Pawn opening position above can be reached by several different move sequences, some of which are shown below.

After both players advance their rook pawns to the middle rank 5, there is a variation in which Black immediately attacks on the second file without the usual left gold fortification (4.

However, White's 23 pawn drop move may also lead to a Double Wing Attack opening.

R-26) is the more common position since the rook will defend Black's side pawn on 76, which could otherwise be captured by White if R-28.

This is the most common move to transition to a typical Side Pawn Capture opening.

The most important constraint on these choices is that White must not allow Black to initiate a bishop trade with their gold on 32 undefended.

One option is for White to prevent Black from initiating a bishop trade by moving a piece to the 33 square.

Otherwise, Black will make the bishop trade leading to a trap that puts White in a poor structure.

One of the major options of Side Pawn Capture is to block Black from initiating a bishop trade.

Although the more common Side Pawn strategies prevent White's undefended gold on 32 by either stopping Black from making a bishop trade or by White making the bishop trade first, the K-41 variation moves their king to the fourth file directly protecting the gold on 32.

[13][14][15] The strategy is covered in Iijima's (2014) book on Rapid Attack (超急) variations of the Side Pawn.

Another answer to Black's bishop threat is for White to retreat their rook back to their camp on rank 2 (...R-82).

With the rook returned to its starting square, it can protect the silver and/or gold on rank 2 rendering Black's bishop attack pointless.

In professional games, these positions are uncommon and often lead to Double Wing Attack variations instead.

Reserve Side Pawn positions are also possible if Black moves their king instead.