The Edge Horse

What does the horse move do?

The first move brings out a horse and makes room for the chariot beside it. With 马二进一 (H2+1), the horse goes from h0 to i2 on the edge file. That empties h0, the point next to the chariot on i0, and the chariot can step onto it with one sideways move.

On the edge, the horse has little to do at first. Red's own soldier on i3 and cannon on h2 block its other moves, so its only move is back to h0. In the course line it stays on i2 while the chariot and the other pieces come out.

Openings are roughly sorted by their first move into cannon, soldier, elephant and horse openings. A horse can open the game in two ways: the horse opening, 马二进三 (H2+3), and the edge horse, which is the rarer of the two. Red's 马二进一 or 马八进九 (H8+9) in the opening is also called a single horse (单提马, dantima).

In the ECCO opening codes, the edge horse has a single code, A02. It belongs to class A, which holds the openings that do not start with the central cannon, apart from the pointing finger.

The course line, move by move

The board below plays the line that the site's opening course teaches for the edge horse. Follow it to see how the chariot uses the point that the horse cleared. The line starts with the opening's standard moves, which a computer engine continued, and the board shows the first twelve moves, six for each side.

The course plays the line on the left wing, starting with 马八进九 (H8+9). This page shows the same moves mirrored onto the right wing, so that they match the archive's cards and board below.

Black answers with a central cannon from h7 and brings out both horses. Red brings out the other horse and also moves the cannon from h2 to the centre file, so each side's central cannon now attacks the other side's centre soldier. Black then pushes the soldiers on g6 and c6, and Red moves an advisor to the centre of the palace. The line ends with the two chariots facing each other on the h-file, where each attacks the other.

How does Black answer?

The board below starts after 马二进一 (H2+1), a position that 152 games in the archive reached. Its arrows show Black's three most common replies, each with its share of those games. The first two, 卒3进1 (P3+1) and the central cannon 炮2平5 (C2=5), are the usual answers to this move, and the third is the horse move 马8进7 (H8+7).

Each of the three cards below plays one of these replies. As Red, prepare for the soldier push first, because Black plays it most often. The central cannon comes next, and the course line shows one way to meet a central cannon.

What is Red's plan?

Red's plan is to bring a chariot into play quickly. In the course line, the horse clears h0, and the chariot steps there on Red's third move. Once the cannon has left h2 for the centre, the chariot goes up the open h-file to h4 on Red's sixth. The edge horse can also work with 担子炮 (danzipao), two cannons side by side, to strike from the side.

Xiangqi Arena teaches five principles for the opening: bring the chariots out quickly, do not move one piece again and again, do not grab soldiers, keep both wings in balance and do not expose the general. In the course line, both sides bring out both horses, neither general moves and no piece is captured. The chariot is Red's only piece to move twice, and Black moves a different piece with each of its six moves.

Common mistakes

A common slip is to play the edge horse and then leave the chariot in the corner. On i2 the horse can only go back at first, so the move pays off once the chariot steps onto the point it cleared. The course line brings the chariot to h0 on Red's third move, and by the sixth it stands on h4.

Another is to forget that the edge horse does not guard the centre soldier. When Black plays a central cannon, as in the course line and the first card, it attacks your soldier on e3 through Black's soldier on e6. If your second move leaves that soldier unguarded, the cannon can take it. The course line brings the other horse to c2, which guards e3 and develops a piece in the same move.

The last is to move the edge horse again soon after. From i2 its only move at first is back to h0, so a second horse move undoes the first and blocks the chariot's point again. Two of your moves are gone, and the horse is back where it began. In the course line the horse stays on i2 through all twelve moves on the board, while Red brings out other pieces.

The edge horse in the archive

Of the 29,164 games between human players in the archive, 152 begin with 马二进一 (H2+1) or its mirror, 马八进九 (H8+9). Red wins 43% of them and Black 26%, and 31% are drawn. Across the whole archive, Red wins 37% of the games and 36% are drawn, so you can compare the edge horse with the average game.

Liu Dianzhong played the edge horse most often as Red, in 13 games, and Lin Hongmin faced it most often as Black, in 4 games. The games last 44 moves on average.

To practise, step through the course line until the moves come easily. The opening's page in the course has two drills on the left wing: one for Red's moves and one where you defend as Black. Then try the edge horse in a few games against the computer. It will not win games by itself, but it brings a chariot into play early.