Saginomiya Joseki.

Static rook, a rapid attack on a ranging rook · castles into Boat · 鷺宮定跡 Saginomiya jōseki

The idea

Aono Teruichi devised this line in the early 1980s, and Yonenaga Kunio made it famous by playing it in title matches; both lived in Saginomiya, in Tokyo’s Nakano ward, which gave it its name.

From the Left Silver-57 position of the Left Silver-46, with White’s silver still on 3b, Black first lifts the 6i gold to 6h, making the Boat a little firmer (the 舟囲いDX: king 7h, golds 6h and 5h), so that White has to commit to the 6d push. Then the rook swings to 3h before anything else, and only then does the third-file pawn go.

After the bishop trade on 3c, Black’s silver comes to 3e and a pawn dropped on 3d presses on White’s camp. The sources rate Black’s position at the end of this line as good; Yonenaga called the line hard work even for professionals.

How it goes together

Both sides’ moves are shown, because this opening is an agreement rather than a system: one player cannot reach it alone, so a one-sided list of moves would be a fiction.

The plan once you are set up

• Build the Boat and the Left Silver-57 position.
• Lift the 6i gold to 6h and wait for White’s 6d.
• Swing the rook to 3h before you attack.
• Push 3e, bring the silver to 4f, trade bishops when White plays 4e, and follow with the silver to 3e and a pawn dropped on 3d.

What to watch for

• White’s waiting move. shogilounge calls the lance to 1b, instead of 6d, White’s best wait against this line, and that is not the line shown here.
• White’s 4e, the counter in every one of these lines: it hits the silver on 4f and opens White’s bishop.
• Yonenaga’s warning: the line is hard work even for professionals.

What it is played against

A Fourth File Rook with a Mino whose silver is still on 3b, waiting with 5d and 6d. ja.wikipedia says the line works against a Fourth File Rook played by either side, unlike the Yamada Joseki.