Openings · 耀龍四間飛車
Yōryū Fourth File Rook.
A Fourth File Rook that stops the king on 3h, one square short of the Mino, with the right gold beside it on 4h.
The idea
Ōhashi Takahiro’s Fourth File Rook keeps the usual setup of the Fourth File Rook: the rook on 6h and the bishop’s diagonal closed by the pawn on 6f. The difference is the king.
It stops on 3h instead of going on to 2h, the right gold comes up to 4h beside it, and the right silver stays at home on 3i. ja.wikipedia lists the three reasons Ōhashi gives: when you attack the edge on the first file your king is further from it, the shape turns easily into a Subway Rook, and the king is off the opponent’s bishop line.
Against a Static Rook Anaguma the plan is not to stop the castle, as the Fujii System does, but to let it be built and then break it from the edge. From 3h the king can stay where it is while the position grows into another castle; a Mynavi editor sums the opening up as the Gold Twins plus a Fourth File Rook.
Ōhashi’s 2020 book made it popular, and he won the Masuda Kōzō Award for it, announced in 2021. No source prints the order of the basic position itself: the moves here are an amateur game played online, as far as the move where White’s player recognised the opening.
How it goes together
Step through the moves, or press play.
Tap a move to jump to it. Arrow keys work once the board has focus.
Every move of the line, with reasons
| # | Black | White | Why |
|---|---|---|---|
| 1 | ▲７六歩 7g7f | △３四歩 3c3d | Open the bishop’s diagonal. White opens its own. |
| 3 | ▲６六歩 6g6f | △８四歩 8c8d | Close the diagonal again with the pawn on 6f: the ordinary Fourth File Rook. White pushes the rook pawn: a static rook. |
| 5 | ▲６八飛 2h6h | △６二銀 7a6b | The rook swings to the sixth file. White’s right silver to 6b. |
| 7 | ▲７八銀 7i7h | △５四歩 5c5d | The left silver to 7h, where it stays in this opening. White pushes the centre pawn. |
| 9 | ▲４八玉 5i4h | △４二玉 5a4b | The king starts walking right. White’s king steps to 4b, toward a Boat castle on the same side of the board. |
| 11 | ▲３八玉 4h3h | △３二玉 4b3b | And stops on 3h. A Mino would take it on to 2h. White’s king reaches 3b. |
| 13 | ▲１六歩 1g1f | △１四歩 1c1d | The edge pawn on the king’s side, the side Black will attack later. White answers on its own edge. |
| 15 | ▲４八金 4i4h | The right gold steps up beside the king, and the silver on 3i stays at home. This is the shape, and the move where White’s player in the source game recognised the opening. |
The plan once you are set up
- Open the diagonal with 7f, close it with 6f, swing the rook to 6h and put the left silver on 7h.
- Walk the king to 4h and 3h, and stop there.
- Push the edge pawn to 1f, then bring the right gold up to 4h. The right silver stays on 3i.
- Answer White’s rook pawn on 8e with the bishop to 7g, as the basic position in Ōhashi’s book has it.
- Against an Anaguma, let it be built and then attack the edge on the first file. Against other setups, ja.wikipedia lists the castles the position can grow into without the king moving again: a Half Yagura, a Doi Yagura, a Right King, a Subway Rook and the Gold Twins.
What to watch for
- Walking on to 2h out of habit. The point of the opening is the square the king does not go to.
- The edge. Ōhashi’s first reason is that when you attack on the first file, your king on 3h is further from it than a Mino king on 2h would be. It is one file further, not out of reach.
- The shape is less settled than a Mino. ja.wikipedia’s list of follow-up castles is long because the right one depends on what White builds.
What it is played against
A static rook with a Boat castle or an Anaguma. en.wikipedia lists what Ōhashi’s book covers: rapid attacks, among them the Left Mino rapid attack and an Elmo castle rapid attack, and slow games against the Static Rook Anaguma, the Matsuo Anaguma, the Left Mino, the Silver Crown and the Silver Crown Anaguma.
The Fujii System meets the Anaguma by attacking before it is built; the Yōryū lets it be built and goes for the edge.
Play it against the bot.
The bot’s search levels, 9 to 12, open from a book that holds two of these openings, the Fourth File Rook and the Yagura; the Mino levels play the openings people play. Either way the review afterwards shows you where the game left the line. Try the line, then try the plan.