Tsume Shogi with Many Pieces in Hand: Which Piece to Drop First

The defending king is on 1一. You have a bishop on 3五, and in hand a rook and two golds. In this position there are 20 checks you can give, and 19 of them are drops.

This article looks at how to decide which piece to drop first when you hold many pieces, using two small positions made for this article. If the notation is new to you, see How to Read Tsume Shogi Solutions. A case where dropping the strongest piece first fails is in Why Can’t I Solve Tsume Shogi? Here the focus is on how to work out the order.

Compare the pieces in hand with the number of moves

Position 1: defender has king 1一. You have bishop 3五. In hand: rook, gold, gold. Mate in 5.

In a mate in 5, you move three times: moves 1, 3 and 5. You also hold three pieces. In composed tsume shogi, the solution is expected to use up every piece in hand (The Finer Rules of Tsume Shogi). Three moves for three pieces means all three moves are drops. A capture would add a piece to your hand and leave you one drop short, so there is no capture either.

That alone rules out moving the bishop, ▲4四角. The other 19 checks are all drops, and the questions left are which piece goes where, and in what order.

Look for squares your pieces protect

Next, look at what the bishop on the board covers. Its diagonal from 3五 runs through 2四 to 1三.

None of your pieces reach 1二, 2一 or 2二, the squares next to the king. Whatever you drop there has no protection, and the king takes it. The protected square is 1三, one step further away. If the king is on 1二, a gold dropped on 1三 gives check from right in front of the king and also covers 2二 and 2三.

So the first move has one job: bring the king to 1二.

Use the rook to pull the king to 1二

The answer is ▲1二飛. The rook is unprotected and will be taken. Being taken is the point.

After △同玉 (the king takes), ▲1三金. The bishop protects the gold, so the king cannot take it, and the gold covers 2二 and 2三. That leaves 1一 and 2一. △1一玉 is met by ▲1二金 (▲2二金 also mates), and △2一玉 by ▲2二金.
After △2一玉, ▲2二金 is mate at once. The rook on 1二 protects the gold, and the gold covers 1一, 3一 and 3二.

△2一玉 loses in 3, so the defender takes with △同玉, and the mate takes the full 5 moves. Rook, gold, gold: all three pieces are dropped.

Give up a gold first, and you are one gold short

If you start with ▲1二金 instead, △同玉 still brings the king to 1二, and ▲1三金 reaches the same shape. The only difference is that a rook is left in your hand instead of a gold.

After △1一玉, ▲1二飛 lets the king out to 2一. A rook does not move diagonally, so it cannot cover 2一. And ▲2二飛 is not check at all, because 2二 is diagonal to a king on 1一.
After △2一玉, ▲2二飛 lets the king out to 1一 or 3一.

A gold covers the two squares diagonally in front of it, so it mates in both lines. The gold is the piece for the last move, and the rook is the one to give up. This is the same idea as “keep the gold for the finish” in Basic Tsume Shogi Tesuji.

▲2一金 and ▲2一飛 are met by △同玉, which puts the king on 2一, where a gold on 1三 gives no check. ▲2二金 is met by △同玉 with the king on 2二. Then ▲1三金 is check, but the king can run toward the 3-file and there is no mate in 5. Where you pull the king to depends on where your protected square is.

Long-range drops let the defender block

A rook can give check from far away. But a distant drop leaves empty squares in between.

After ▲3一飛, the defender drops a piece on 2一 and there is no mate. In tsume shogi the defender holds every piece that is not on the board or in your hand, so a pawn, lance, knight, silver, gold, bishop or rook can go there.
▲4一飛 through ▲9一飛 are met by △2二玉.
▲1三飛 is met by △2一玉, and ▲1四飛 through ▲1九飛 by △2一玉 or △2二玉.

Distant drops make the list of candidate checks long. With many pieces in hand, the rook alone accounts for 16 checks here. Blocks are covered in What Is Aigoma?

When the bishop goes first and the rook last

The last move is not always a gold.

Position 2: defender has king 1一. You have a tokin (promoted pawn) on 3三. In hand: bishop and rook. Mate in 3.

In a mate in 3 you move twice, and you hold two pieces. By the same reasoning as before, both moves are drops and the tokin does not move.

Of the squares around the king, the tokin protects only 2二. The answer is ▲2二角. The king cannot take the bishop and has to go to 1二 or 2一.

After △1二玉, ▲1一飛 is mate. The rook gives check down the file and also covers 2一. The bishop covers 1三 and the tokin covers 2三.
After △2一玉, ▲1一飛 is mate again. This time the rook checks along the rank and also covers 1二. The bishop covers 3一 and the tokin covers 3二.

The bishop on 2二 protects the rook on 1一. From 1一, a piece can check a king on either 1二 or 2一, and the rook does it because it moves both along the file and along the rank.

Reverse the order with ▲1二飛 or ▲2一飛, and the rook has no protection. △同玉 takes it and there is no mate.

In Position 1 the gold made the last move, and in Position 2 the rook did. Which piece goes last is decided by the mating shape, not by how strong the piece is.

A way to work out the order

When a problem with many pieces in hand looks wide open, one way to narrow it down is in this order.

Compare the pieces in hand with your number of moves. If they are equal, every move is a drop and nothing is captured.
Find the squares your pieces on the board protect.
Work out which piece on which square gives mate on the last move, and keep that piece in hand.
Use the other pieces to bring the king to where that shape works. Pieces you can afford to lose are used here.
When you drop a rook or bishop at a distance, read the blocks on the squares in between.

Steps 3 and 4 read backward from the mating shape. How this works in longer problems is in Reading 7-Move and 9-Move Tsume Shogi Without Getting Lost.

Trying drop orders in Shogi365

Shogi365 contains tsume shogi from mate in 3 to mate in 9, with 1,000 problems for each length, 4,000 in total. You choose by length.

You solve by playing on the board yourself. Any check, right or wrong, can be played, and the defender replies automatically. If you don’t mate within the move count, the attempt fails, and you can retry up to three times. A hint lights up the piece and the destination square of the next correct move. When that move is a drop, the piece in your hand blinks, so you can see which piece goes first. You still play the move yourself.

All problems are free to solve. The app shows ads, and a one-time Remove Ads purchase turns them off. How to use the app is in Getting Started with Shogi365.