Shogi opening


A shogi opening is the sequence of initial moves of a shogi game before the middle game. The more general Japanese term for the beginning of the game is .
A jōseki is the especially recommended sequence of moves for a given opening that was considered balanced play at one point in time for both sides by professional players. s also typically include commentary about the possible reasons to deviate from the especially regarding blunders.
Note that not all openings have s. For example, trap openings like Demon Slayer, while they may have standard moves, are considered to favor one player and are not balanced play. Thus, the Demon Slayer opening is not a jōseki.

Introduction

The very first opening moves in most games are pawn pushes. In particular, most games start with two types of pawn pushes. A player can move the rook pawn forward as the first type of pawn push, or, more commonly, advance the seventh file pawn to open the bishop's diagonal for attacking as the second type of pawn push. Strategically, these two moves aim to activate the two most powerful pieces in the game.
Furthermore, these two types of pawn pushes are the most common moves for both Black and White. Thus, almost all games will start with one of the four possible combinations of these two pawn push types.
With a bishop diagonal first move, it is common to exchange bishops by having one capture the other. This allows each player to put their newly captured bishop into play anywhere on the board on their next move although care must be taken to avoid weaknesses in defense which may allow for a bishop drop from their opponent. However, it is not advantageous to exchange bishops if your opponent has a better defensive setup or more lines of attack. Moreover, making a bishop exchange constitutes tempo loss, so it is not advised without a good reason. Opening the bishop diagonal as the first move is the most flexible first move, which leads to the largest number of opening possibilities. Additionally, although P-76 and P-34 may occur as the first two moves allowing for a bishop trade off, it is always possible that either Black or White can prevent an early bishop exchange by closing their bishop diagonal with a subsequent pawn push – P-66 for Black or P-44 for White.
With the rook pawn first move, the intention is usually to keep the rook on its initial file on the player's right side of the board and develop an attack on this side with support from the rook. Compared with opening the bishop diagonal for the first move, a rook pawn push limits the range of opening possibilities for the player and for their opponent. Additionally, it signals to their opponent that they will be playing against a Static Rook position. Thus, 1. P-26 is comparatively more informative of a player's planned strategy.
A third common first move is to push the central pawn. However, P-56 is an order of magnitude less common than the other P-76 and P-26 moves. With the central pawn push first move, the player most often is preparing to move their rook to the central fifth file in order to support this central pawn push. However, other configurations are possible.
Many common opening attacks involve advancing a silver and ideally pawns, protected by other pieces. Because silvers have more possibilities for retreat, silvers are generally considered superior as attacking pieces in the opening and middle game while golds better defend their sides and are superior as defensive pieces. It is common practice to defend the king with three generals, two golds and a silver.
Because defense is so important, and because shogi pieces are relatively slow movers, the opening game tends to be much longer in shogi than in western chess, commonly with a dozen or more moves to shore up defenses before the initial attack is made. As part of the defense, typically the king is moved to the side in a castle with three generals. Leaving a king on its original square may be a particularly dangerous position.
Over the past 400 years, Japanese professional players have invented various , which determine moves and sequences which are thought to be the best for a particular situation. It also covers a branch of different variations within an intricate strategy, including alternative options and the certain consequences that some moves may bring.
Shogi openings are generally slower than that of western chess, due to the larger board and less mobile pieces. But since a quick offense will leave a player's home territory open to drop attacks as soon as pieces are exchanged, one aim of the opening is to build up defenses for the king.

Classification

Rook position

Openings for even games are traditionally classified by the position of a player's rook – specifically whether it remains on its starting square or moves to a different square. In this binary classification, Static Rook openings are where the offense is supported by the rook in its original position. Ranging Rook openings are where the rook moves to the center or left of the board to support an attack there, typically with the idea of allowing the opponent to attack while arranging a better defense and aiming for a counterattack. Before the modern era, shogi openings were categorized by both the position of the rook and by the position of bishop.
Openings are further subcategorized based on the opening each player chooses:
  1. Double Static Rook
  2. Static Rook vs Ranging Rook
  3. Ranging Rook vs Static Rook
  4. Double Ranging Rook

    Interaction with castles

As the most powerful piece on the board, the rook invites attack, and in most cases, especially for inexperienced players, it is a good idea to keep the king well away from the rook. Relatedly, the Static vs Ranging classification corresponds to castle development: static rook positions with the rook on the right side of the board tend to have castles on the left side of the board while ranging rook positions tend to have castles on the right side.
The adjacent diagram shows a Static Rook vs Ranging Rook game. Here Black is playing Bear-in-the-hole Static Rook with their rook remaining on its starting square and a Bear-in-the-hole castle on the left side of their board while White is playing Central Rook in which their rook has moved to the central fifth file and their king placed in a Kimura Mino castle on the right side of their board.
Certain castles are traditionally thought to be more appropriate for particular Black/White opening combinations. For example, Fortress castle is a strong defense against an opponent's headlong Static Rook attacks, but it is a weaker choice for a Ranging Rook opponent as the Fortress does not provide as much defense against side attacks, which are likely to occur when the Ranging Rook player's rook breaks through the right side of Black's camp.

Static Rook

Static Rook openings usually have the player's rook at its start position, which is second file for Black and the eighth file for White.
Most Static Rook openings coincide with a castle development on the player's left side of the board. In the adjacent diagram is an example of a castle built on the left side of the board paired with a Static Rook position. The castle is a Left Silver Crown Bear-in-the-hole.
Further classification of Static Rook positions depends on response to the opponent's position of either Static Rook or Ranging Rook. Thus, there are the two types of Static Rook positions: Double Static Rook formations and Counter-Ranging Rook formations.
Examples of Static Rook openings are below.
Ranging Rook openings are positions in which the rook moves to the center or left of the board to support an attack there.
Most Ranging Rook openings coincide with a castle development on the player's right side of the board. In the adjacent diagram is an example of a castle built on the right side of the board paired with a Ranging Rook position. The castle is a Mino castle.
Examples of Ranging Rook openings:
The other traditional main categorization of shogi openings is based on the timing of a player's attack within the opening. A rapid attack variation of an opening has a player initiating an attack with only a weaker castle developed first or with very minimal castle development and sometimes with no castle development at all. The opposite type is a slow game in which both players spend much of the opening developing strong castles.
For example, Fourth File Rook is an opening that has one player moving their rook to the fourth file if playing as White while the opponent plays Static Rook with their rook in its start position. Fourth File Rook has several rapid attack variations and slow game variations that are identified by the attack formations of the Static Rook player. In the rapid attack variations, the Static Rook player constructs a Boat castle – a weaker castle – and quickly builds an attack formation. In the slow game variations, the Static Rook player will build stronger castles such as Bear-in-the-hole castle or Left Mino castle.