Super High Speed Silver.

Static rook, against the Cheerful Central Rook · castles into Boat, with the silver on 6h · 超速▲３七銀 chōsoku san-nana gin

The idea

The Super High Speed Silver is Black’s quick answer to the Cheerful Central Rook. White’s rook stands on 5b and its pawn on 5e, and that pawn is what shuts White’s own bishop in. Black pushes the pawn to 3f and brings the right silver straight up through 4h and 3g to 4f, with the king still on 6h. Here White meets it silver for silver, with its own silver on 4d.

Then the king steps to 7h and the left silver comes out too, through 6h and 7g to 6f. Now both silvers bear on the 5e pawn, with the bishop lined up behind the one on 6f, and without that pawn the Central Rook has little left to attack with. Hoshino Yoshitaka devised the plan as an apprentice and won the 2011 Masuda Kōzō Award for it.

For a time it worked so well that fewer players chose the Cheerful Central Rook, and both sides have kept refining it since. The 3g in its Japanese name, 超速▲3七銀, is the silver’s second step.

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

• Start from the Cheerful Central Rook’s basic position: White’s rook on 5b, pawn on 5e, bishop on 3c. Push 3f and bring the right silver to 3g and then 4f. Leave the king on 6h for now.
• Castle a little: king to 7h and the left silver to 6h. That is the Boat with the silver on 6h, the form ja.wikipedia says appears often in this opening.
• Bring the left silver on, to 7g and then 6f. With both silvers aimed at 5e and the bishop behind the 6f silver, you threaten to take the pawn with the left silver.
• If White has met your silver with its own on 4d, it defends 5e as many times as you attack it. Play the gold to 5h, the knight to 3g and the rook to 2i. Then jump the knight to 4e to drive the bishop off 3c, and take on 5e once the bishop no longer guards it.

What to watch for

• An early 5f push by White. If White exchanges the centre pawn while your silver is still on 3g, trade bishops on 3c and drop the bishop on 6e. shogi-joutatsu shows that White cannot stop it from promoting.
• Moving the king to 7h too early. ja.wikipedia warns that White’s 5f push then lets White’s rook come round to 5f and on to 7f.
• The knight to 4e before the rook to 2i. With the rook still on 2h, White can give up its rook on 5e and drop a bishop on 3g, forking your rook and your silver.
• The amount of detail. ja.wikipedia says the static rook side cannot handle this opening without knowing the details, and shogi-rule.com calls it a high hurdle for amateur players.

What it is played against

The Cheerful Central Rook, played by White. White’s main choice is whether to castle first (king to 6b, 7b, 8b) or to meet your silver with its own, as here. en.wikipedia says White developed the second because Black did well against the first.

The other replies the sources list are the silver or the gold to 3b, and Sugai’s line, which pushes the fourth-file pawn to 4d and 4e.

Black has other answers to the Cheerful Central Rook as well: an early bishop trade (Maruyama’s Vaccine), the Super Rapid Attack with the gold to 5h, and a Static Rook Anaguma.