In the opening, the cannon is often the most dangerous piece on the board. The central cannon points at the enemy general from move one, and there are pieces everywhere to use as screens. In the endgame the picture reverses. The board is empty, screens are rare, and a cannon on its own becomes one of the weakest attacking pieces there is.
Understanding this changes how you play the whole game, because it tells you when to keep your cannon and when to trade it — and why you should almost never give away your own advisors when you still have a cannon.
The cannon's problem in the endgame
The cannon (C, Vietnamese Pháo) moves like a chariot, but it can only capture — and only give check — by jumping over exactly one piece. With no piece between it and the enemy general, it does not check. With two pieces between, it does not check either.
In the middlegame this is rarely a problem. In the endgame, with only a few pieces left, the cannon often has nothing to jump over. It can control lines when it is not checking — a cannon standing on a rank still blocks the general from crossing — but it cannot threaten mate by itself.
A lone cannon cannot beat a bare general
With only a cannon and your general against the enemy general, the cannon has no screen available at the decisive moment. You can drive the general around, but you cannot deliver checkmate or build a no-move win reliably. This ending is a draw.
That is a big difference from the chariot, which wins against a bare general easily, and from the horse, which wins with the help of the general and the no-move rule.
Your advisor as the screen
Everything changes if you keep one of your own advisors. The advisor stays inside your palace, but it can serve as the screen for your cannon along a file.
Look at how little material this takes: a cannon, one advisor, and the general. The advisor never leaves its palace, yet it is the piece that makes the mate possible. The general does its usual job of controlling a whole file from across the board.
This is why the general principle for cannon endings is simple: cannon plus advisor can usually force a win against a bare general; cannon alone cannot.
Other screens you can use
The advisor is the most reliable screen because it cannot be chased away easily. But any piece works:
- Your own soldier. A soldier in front of the enemy palace can be the screen for a cannon behind it on the same file.
- Your own elephant. Elephants stay on your half of the board, but on a file they can still act as a screen for a cannon farther back.
- An enemy defender. If the defender still has an advisor or elephant, it can become the screen for your cannon's check. That is one reason cannon endings against a single defender can sometimes be won.
Cannon against defenders
Against a full set of advisors and elephants, a lone cannon has no realistic winning chances. The defenders block lines and give the defender endless waiting moves. Even with an extra soldier, breaking a full defence with a cannon is a long and uncertain process.
Against fewer defenders, the results depend on the details. The more screens are available to the cannon — including the defender's own pieces — the better its chances.
What to trade before the endgame
This is where the knowledge pays off:
- If you will be left with a cannon, keep your advisors. Giving up an advisor in the middlegame for a small gain can cost you the screen you need later.
- If your opponent will be left with a cannon, trade off their soldiers. Fewer pieces on the board means fewer screens.
- If you have a choice between keeping a cannon or a horse for the endgame, think about screens. With many soldiers left, the cannon can be strong. With an almost empty board, the horse is often the better piece.
Many players remember this with a traditional saying from Chinese xiangqi: in the opening the cannon is stronger, in the endgame the horse. Like every saying it is a rule of thumb, not a law — but it points in the right direction.
Practical tips for cannon endings
- Put your general on the right file first. As in every xiangqi endgame, your general's control of a file is half the work.
- Bring the cannon behind your advisor. Line up cannon, advisor and enemy general on one file, and the check arrives by itself.
- Use the cannon to cut the board. Even without checking, a cannon standing on a rank or file stops the enemy general from crossing it.
- Beware of the reverse screen. Your pieces can also be screens for the enemy cannon. Count the pieces on every line leading to your own general.
Practise it
- Set up the diagram on a physical board. Remove the red advisor and try to win — you will find there is no way.
- In games against the computer at the home board, when trading pieces late in the game, ask yourself whether your cannon will still have a screen.
- Compare with chariot endgames, horse endgames and soldier endgames.
A worked plan with cannon, advisor and general
Suppose you reach the ending from the diagram, but the pieces are scattered: your cannon on a wing, your advisor on its home point, your general in the centre of its palace, and the enemy general wandering in its own palace. A calm plan looks like this:
- General first. Step your general to the file next to the centre. From now on the enemy general cannot use that file.
- Advisor to the right file. Bring the advisor to the palace point on the file where you want the enemy general to end up — usually the other side file.
- Cannon behind the advisor. Slide the cannon onto the same file, below the advisor. Now any time the enemy general stands on that file, it is in check.
- Squeeze. The enemy general has only a few points left. Use cannon moves along the ranks to take them away one at a time, and look for the moment when it has to step onto the file where the cannon and advisor are waiting.
The details vary from position to position, but the order — general, screen, cannon — almost never changes.
Frequently asked questions
Can a cannon and general beat a bare general?
No. Without any other piece, the cannon has no screen when it needs one, and the ending is a draw.
What is the easiest way to win with a cannon in the endgame?
Keep an advisor. The advisor serves as the cannon's screen on a file, and together with your general's control of another file, you can mate a bare general.
Is the cannon better than the horse in the endgame?
Usually not when the board is almost empty, because the cannon lacks screens. With soldiers still on the board, the cannon can be strong.
Can the enemy's pieces be my cannon's screen?
Yes. A screen can be a piece of either colour. An enemy advisor on the right file can let your cannon give check.
Should I trade my cannon when entering the endgame?
It depends on the screens that will remain. If the board will be nearly empty and you have no advisors, a horse or a soldier is often more valuable than the cannon.
