Castles · 左玉
Left King.
The king goes left, to his own rook’s side: king 7h beside a bishop on 6h, silvers on 6g and 6f, the rook down on 8i, and one gold left on 3h to hold the right.
How it goes together
The king stands on 7h, with the bishop pulled back beside him on 6h and the left gold on 5h. In front of them the knight is on 7g, and the two silvers stand one above the other on 6g and 6f, holding the 6e pawn; the JSA column counts the 6f silver an important defender. The rook has gone to the eighth file and down to 8i, on the bottom rank. On the right there is only the gold on 3h, which nothing guards. The 6g silver is the only piece that guards the king; the king and the 5h gold guard that silver, and the bishop too.
Move by move
Black only, from the start, in the order of the Japan Shogi Association’s castle column: the first six moves are an ordinary double ranging rook opening with the rook on 8h, then the right silver crosses to the centre, the pawns take space, and the king walks left last.
Step through the moves, or press play.
Tap a move to jump to it. Arrow keys work once the board has focus.
Twenty moves. The column adds two refinements: if the rook pawn can be exchanged first (push it to 8d, take back, then drop the rook to 8i), that is better than simply pulling the rook back, and the king can also come across earlier, before the eighth-file pawn moves.
What it is good against
Distance and balance. The opponent’s rook is aimed at the right side, and the king is not there; ja.wikipedia says the king has room and plenty of escape squares, with few gaps for drops. The JSA column adds that the opponent’s castle is much harder, but after a bishop trade its lopsided camp has more gaps than this one. The rook on the bottom rank is aimed at the head of the opponent’s king (ja.wikipedia).
Where it breaks
The king is thin, and the JSA column says it takes skill to handle. The right side is held by one gold (ja.wikipedia), and the column calls it weak to a rook trade. It needs the rook on the eighth file: with the rook on 7h the king cannot reach 7h, and with it on 6h the bishop cannot drop back there (JSA). ja.wikipedia says it does well against a Ranging Rook Anaguma and has a harder time against a Right Yagura.
When to build it
Double Ranging Rook games, with the rook on the eighth file as in an Opposing Rook (the JSA column, Shogi Wars). Takada first used it from a static rook start against a Fourth File Rook (ja.wikipedia). The column suggests it to players who like balance or want to arrange their pieces freely, and notes that few play it, so opponents seldom know it.
Build it at the board.
The app’s lesson walks the king into a Mino one step at a time, and its review names the castle you were building when a game turned.