Horses and cannons are the two pieces that make xiangqi feel different from international chess. The horse attacks from awkward angles and can be blocked at its leg; the cannon needs a screen to capture or check. Put them on the same file with the horse in front and the cannon behind, and each one covers the other's weakness. The horse becomes the cannon's screen, and the cannon's check comes with the horse already controlling the general's side points.
Vietnamese players call this pattern Mã hậu Pháo — literally "horse in front, cannon behind". It is one of the classic mates every club player learns early.
The pattern
Look at the three things that happen at once:
- The cannon checks. Between the cannon and the black general there is exactly one piece, the red horse. That is a legal cannon check.
- The horse covers the side points. From two points in front of the general on the same file, the horse attacks both points next to the general on the back rank. Its leg point — the point directly in front of the general — is empty, so both jumps are available.
- The point in front of the general is on the cannon's file. If the general steps forward, it is still on the file with the horse as the only piece in between. Still check.
Nothing black can capture the horse or the cannon. The only way to stop a cannon check by blocking is to put a second piece on the line, and the only empty point on that line inside the palace is the one directly in front of the general — Black has no piece that can reach it. It is mate.
Notice also that the two red and black generals share the centre file here, but the horse and cannon stand between them, so the position is legal.
Why the horse is the perfect screen
A cannon's screen can be any piece. But most screens do nothing else. A soldier used as a screen just sits there. The horse, standing two points in front of the enemy general, does two jobs: it makes the cannon's check possible, and it attacks the points the general wants.
This also works in reverse as a defensive trap for the defender: if the black general steps to the side before the cannon arrives, it walks into the horse's attack. The horse on that square is dangerous on its own.
Getting the horse to the right square
The target square for the horse is on the enemy general's file, two points in front of the general. When the general is at home, that is the front centre point of the enemy palace.
Typical routes:
- Through the centre. A horse that crosses the river on the centre file can jump to the target in one or two moves if the leg points are clear.
- From the flank. A horse working on the wing can swing in via the points next to the palace. This takes longer but is harder to see coming.
The cannon usually arrives first — very often it is the central cannon from the opening (C2=5 in WXF notation) that has been on the centre file for the whole game. The horse lands last, and its landing is the check.
Variations
Horse on a side file
If the enemy general has moved to the file next to the centre, the same idea works on that file: horse two points in front of the general, cannon behind it on the same file. The horse's side attacks then cover the general's new neighbours.
Adding a chariot
When the defender has one advisor on the centre point of the palace, the pure pattern may fail. Adding a chariot that controls a rank or file around the palace usually restores it. Many real games finish with horse, cannon and chariot all taking part.
The discovered check
Sometimes the horse is already on the file between the cannon and the general, but not on the ideal square. Moving the horse away gives a check from the cannon only if another piece remains as a screen; moving it to the ideal square keeps the screen and adds the horse's attacks. Always count the pieces on the line before and after the horse moves.
How to defend
- Occupy the landing square. A piece of yours on the point two in front of your general stops the horse from landing there.
- Block the horse's leg. The horse reaches its target through a leg point. Put a piece there and the horse cannot come.
- Break the file. A second piece on the file between the cannon and your general makes the cannon's check impossible, because a cannon needs exactly one screen.
- Move the general early. A general that has stepped to the side of the palace, on a file that is not attacked, is much harder to catch with this pattern.
Practise it
- Set up the diagram and check Black's options one by one. Then move the red horse one point sideways and see how the mate falls apart.
- Play the computer with the central cannon opening at the home board. Every time your horse crosses the river, ask whether it can reach the point two in front of the enemy general.
- Compare with the double cannon mate, where the screen is another cannon, and the smothered mate, where the horse gives the check itself.
Frequently asked questions
What does Mã hậu Pháo mean?
It is Vietnamese for "horse in front, cannon behind" — the horse stands between the cannon and the enemy general and acts as the cannon's screen.
Why doesn't the general just step sideways?
Because the horse, standing two points in front of the general on its file, attacks both side points.
Can the defender block the check?
A block would put a second piece in front of the cannon, which does stop a cannon check. So the defender needs a piece that can reach the point between the horse and the general. In the classic picture, no defending piece can — which is why keeping an advisor able to reach the centre of the palace is a good defensive habit.
Does the red general matter here?
Only indirectly. The two generals may stand on the same file, as long as pieces stand between them. In the diagram, the horse and cannon are between them.
Is this mate common in real games?
Yes. The central cannon is the most popular opening in xiangqi, and a horse reaching the enemy general's file with the cannon behind it is a natural follow-up.
