### 2.3 Mating problems ¶

One good way to improve at shogi is to solve mating problems. There are several types of these problems, but the most common is called a “tsume-shogi” problem, or “tsume” problem for short. In a tsume problem, all pieces that are not on the board are assumed to be in the opponent’s hand (except for your King, which is usually not shown). Every move you make must be check until the final checkmate. Your opponent may play any piece on the board or drop any of his pieces in hand in order to prevent the mate. In a properly constructed tsume problem, all of your pieces on the board and in hand must be essential to the solution. One consequence of this is that all of your pieces in hand must be played during the solution. There should only be one correct solution for the given number of moves. Tsume problems use Japanese-style move numbering; thus, a problem where you move (and give check), your opponent moves, and you move to give checkmate is called a three-mover. Here is a really trivial three-mover:

       3    2    1
    ----------------+
     |    |    |    |  a
    ----------------+
     |    |    | wK |  b
    ----------------+
     |    |    |    |  c
    ----------------+
     | bN |    |    |  d
    ----------------+
     |    |    |    |  e
    ----------------+
     |    | bN |    |  f
    ----------------+

    Black in hand: S, G

Here, Black plays G*2b, White plays K1c, and Black plays G*1d mate. More typical tsume problems range from 5 moves to arbitrarily high numbers of moves, and they can be quite brain-busting. Tsume problems may seem artificial, but in the closing stages of the game where both players have a lot of pieces in hand, it is often necessary to give check at every move, or else your opponent will start a counterattack and will mate you before you mate him. A tsume problem is a worst-case scenario for the attacker: you have to mate your opponent even though he has every piece not on the board in hand, which means you have to develop sharp attacking skills. Many more tsume problems can be found on the internet; I particularly recommend Patrick Davin’s “Shogi Nexus” (see References and links).