Shogi Promotion and Drops: How They Differ from Chess

If you already play chess, most of shogi feels familiar. There is a king to trap, there are pieces that slide and pieces that step, and the game ends in checkmate. Two rules are new, though, and they are the ones chess players trip over most: promotion works differently, and captured pieces come back into play.

This post explains both by comparing them with chess. The rules follow Article 5 of the Japan Shogi Association’s game rules. How each piece moves is in How Shogi Pieces Move, so here I stick to promotion and drops.

Promotion: who, where and when

In chess, only a pawn promotes, only when it reaches the last rank, and it has to. In shogi almost every rule here is different.

Who promotes. Six of the eight piece types can promote: rook, bishop, silver, knight, lance and pawn. Only the king and the gold cannot.

Where. The promotion zone is the three ranks on your opponent’s side, not just the last rank. Under the rules, a piece may promote when it is inside the zone before or after its move. That gives three cases:

• moving into the zone, for example a silver stepping from the fourth rank to the third;
• moving within the zone, for example a silver stepping from the third rank to the second;
• moving out of the zone, for example a bishop inside the zone sliding diagonally back out of it.

The third case surprises people. A move that leaves the zone can still promote. The simple way to remember it: if either the starting square or the landing square is in the zone, you can promote.

Whether you must. A chess pawn cannot stay a pawn. In shogi, promotion is optional. You can choose to stay unpromoted, which is called narazu. The exception is a piece that could never move again: a pawn or lance on the last rank, or a knight on either of the last two ranks, must promote. Leaving such a piece is a foul, covered in Fouls in Shogi.

What it becomes. A chess player picks from queen, rook, bishop and knight. In shogi there is no choice of piece. Each piece has one promoted form, shown on the back of the piece. You just flip it over.

Going back. In both games a promoted piece stays promoted on the board. The difference shows up when it is captured, which I come to below.

The promoted pieces

The promoted forms fall into two groups.

• The rook becomes a dragon and the bishop becomes a horse. Each keeps all its old moves and adds the king’s one-step moves.
• The silver, knight, lance and pawn all move like a gold. A promoted pawn is called a tokin.

The rook and bishop lose nothing by promoting, so you will usually promote them. The silver, knight and lance each lose something: the silver its backward diagonals, the knight its jump, the lance its long forward reach. Those three are worth a second thought. In tsume shogi, declining promotion is often the key move, and why is in Not Promoting in Tsume Shogi.

Chess has the same kind of decision in the other direction. Promoting to a rook or knight instead of a queen is sometimes right, and that is in Underpromotion. For a beginner in shogi, “promote the rook and bishop, think once about the silver, knight and lance” is enough to start with.

Drops: captured pieces come back

In chess, a captured piece leaves the game for good. In shogi, a piece you capture becomes yours. The rules call it a piece in hand.

If you capture a promoted piece, it goes back to its original side. Capture a dragon and you get a rook. Capture a tokin and you get a single pawn.

On your turn, instead of moving a piece on the board, you can place one piece from your hand onto the board. This is a drop, and it counts as your whole move. You cannot move a piece and drop one in the same turn.

Where you can drop, and where you can’t

A piece in hand can be dropped on any empty square: in your own camp, in your opponent’s, even right next to the enemy king. There are a few limits.

• Always unpromoted. A dropped piece goes down on its original side, even inside the promotion zone. It can promote the next time it moves.
• Nifu, two pawns. You cannot drop a pawn on a file that already has one of your unpromoted pawns. A tokin does not count as a pawn.
• No dead pieces. A pawn or lance cannot be dropped on the last rank, and a knight cannot be dropped on the last two ranks.
• Uchifuzume. You cannot drop a pawn to give checkmate. A pawn drop that gives check is fine, and so is mating by pushing a pawn already on the board.

Uchifuzume has some tricky shapes, and for now “you can’t mate with a dropped pawn” is enough. The details are in Uchifuzume Explained.

What drops do to the game

Because of drops, shogi never thins out. In chess the endgame often gets quiet as pieces come off the board. In shogi, captured pieces pile up in hand, so the attacking options grow, and the endgame is usually the sharpest part of the game.

Material also counts twice. When you lose a piece, you are one piece down and your opponent is one piece up. The gap opens from both ends. And that changes how you think: less about holding on to every piece, more about where the pieces you have taken will do the most damage.

One view is that the freedom to drop anywhere is what makes shogi feel so wide. If you look only at the board, you miss half the position. Once you get used to glancing at your opponent’s pieces in hand, the game starts to look different.

Where chess players trip up

Forgetting the opponent’s hand. In chess, a piece that has left the board is gone. In shogi, every piece your opponent has captured can come back on any move. Each empty square next to your king is a square where a piece can be dropped.

Expecting to choose the piece. There is nothing to pick. The piece flips to its fixed promoted side, and the real decision is whether to flip it at all.

Promoting only on the last rank. The zone is three ranks deep, and moving out of it counts too.

Capturing diagonally with a pawn. A chess pawn takes diagonally forward. A shogi pawn takes the piece straight in front of it, the same way it moves.

The wider differences between shogi, go and chess are in Shogi, Go and Chess: The Differences.

Learning promotion and drops in Mindsports

StudyX Mindsports is an app with 12 mind games, including shogi, go and chess. It runs on iPhone, iPad and Android.

In shogi, when you make a move that can promote, the app asks “Promote?” and shows the piece both ways: the promoted piece with “Promote” and the unpromoted piece with “No”. You can also tap “Cancel” and pick a different move. On a square where the piece would have no further moves, it promotes without asking.

Your pieces in hand sit beside the board. Tap one, then tap an empty square to drop it. The app won’t let you drop onto a nifu file, a square where a pawn drop would mate, or a square where the piece could never move, so you can get used to drops without worrying about fouls.

In Mindsports chess, by contrast, a pawn that reaches the last rank becomes a queen automatically. The promotion decision you make in the app is the shogi one.

The shogi beginner lesson teaches the rules through tap-to-answer quizzes. After that, you can play the CPU from Lv.1 to Lv.50. Win and the level goes up by one, lose and it goes down by one. The games and beginner lessons are free, with ads. Each game’s first advanced lesson is free too, and a one-time purchase opens the rest and removes the ads. How to use Mindsports is in Getting Started with StudyX Mindsports.