Golden Hook Horse in Xiangqi: The 金钩马 Checkmate

Gold, a hook and several names

金 means gold and 钩 means hook, so 金钩马 is the golden hook horse. Strictly speaking the name belongs to the Horse and the point it stands on, not to the mate. Chinese glossaries put that point on the opponent's second rank, on the second file in from either edge, which is the point right in front of where the opponent's Horse begins the game.

Names for the finished combination vary. English teaching sites call it the golden hooked horse checkmate, and xqinenglish gives it the Chinese label 腋车挂 (yè jū guà): 腋 is armpit, 车 is chariot and 挂 is to hang, the same 挂 found in 挂角马, the palcorner horse. Chinese lists of basic mates describe the same mechanism as 白马现蹄, the white horse shows its hoof: a Chariot is given up to pull a defender off its post, so that a Horse on the second rank can check from the palace corner.

Whatever the original picture behind the gold hook, it suits the move. The Horse does not charge in through the front of the palace. It curls round from the side, one short leap into the corner.

Why the centre Advisor is the real target

Picture Red attacking Black's palace, with Red at the bottom and left and right read from Red's side. From the hook point on the left, a Horse reaches two palace points: the back corner on that side and the front corner on the same side. Both leaps pass through the same leg, the point right next to the Horse on the inside. That point is the trough point used by the lying trough horse, and while it stays empty the Horse is loaded.

The front corner is where the Horse wants to land, because from there it checks a General on its home point. The trouble is that a front corner is exactly what a centre Advisor guards. An Advisor moves one point diagonally, so from the middle of the palace it covers all four corners. Jump too early and the Horse is simply taken.

So the combination starts with a sacrifice. A Chariot on the rib file, the file running along the edge of the palace, crashes into the back corner. If the Horse covers that corner, the General cannot take the Chariot back, and the centre Advisor has to. The moment it does, the front corner has no guard.

The combination on a board

Set up this position. Black's General is on its home point. One Black Advisor stands on the back corner of the palace on Red's left and the other in the palace centre, and a Black Elephant sits on the middle point of the palace's front edge. Red has a Chariot on the left rib file on its own side of the river, with nothing between it and Black's back rank, a Horse on the left golden hook point, a Soldier on the middle point of the palace's right edge, and its General at home. Red to move.

First, the tempting move that fails. If the Horse jumps straight to the front-left corner, it does give check, but the centre Advisor takes it. We ran the position through the rules engine behind XiangqiPlay, and that capture is Black's only reply, a perfectly good one. There is no mate in one anywhere in the position.

Now the real move. The Chariot runs up the rib file and takes the Advisor on the back corner, with check. Black's choices are thin. The General cannot take the Chariot, because the Horse guards that corner. It cannot step right, since that point lies on the Chariot's rank and the Soldier covers it as well. The palace centre is occupied by its own Advisor. So the centre Advisor must capture the Chariot, and the engine confirms it is the only legal move.

Then the Horse jumps to the front-left corner. Check, and mate. The General's left side is now filled by the Advisor that just recaptured. Its right side and the palace centre are both covered by the Soldier. The Advisor in the corner can only step into the centre, so it cannot reach the Horse, and no Black piece can occupy the leg point between the Horse and the General. The engine finds no legal reply.

What the Soldier is for

Take the Soldier off the board and play the same two moves. The sacrifice still forces the recapture, but the Horse check is now harmless, because the General walks into the palace centre or across to the right back corner. The hook Horse only works on its own side of the palace, so a partner has to hold the far side.

That partner does not have to be a Soldier. Change the setup so that Black's second Advisor stands on the right back corner instead of the left, put a second Red Chariot on the right edge of Black's second rank, and run the first Chariot onto the empty left back corner. The centre Advisor again has to take it. When the Horse jumps in, the second-rank Chariot covers the palace centre and Black's own Advisor blocks the right corner. That version is mate too.

Finding it in your own games

Three things have to line up. You need a Horse on the hook point or one leap from it; from Black's soldier rank, a Horse on the edge file or on the third file from the edge reaches the hook point in one move, provided the point directly in front of it is empty. You need a Chariot on the rib file on the same side, with a clear run to the back corner. And you need something already watching the General's other exits.

When you see the first two, look hard at the third, because it decides whether the sacrifice is brilliant or just a lost Chariot. Count the General's exits after the recapture, not before. In the example, the left side was about to be filled by Black's own Advisor, a gift that the sacrifice itself creates.

The hook point also connects this mate to others. It sits right beside the trough point, which is why the double horse mate, 双马饮泉, often uses one Horse on the hook point and the other in the trough. If a Horse of yours is heading for the second rank, keep both ideas in view.

How Black stays out of it

The cheapest defence is the leg. Both of the hook Horse's leaps into the palace pass through the trough point, so a Black piece standing there switches off the threat to the back corner and the front corner at once. Advisors and Elephants can never stand on the trough point, so that job needs a Chariot, Horse or Cannon.

Second, do not let the centre Advisor become overloaded. If it is the only guard of a front corner and also the only piece able to recapture on a back corner, one sacrifice breaks both duties. Keeping a second defender near the corner, or keeping the General's other exits free, gives Black a different answer to the Chariot.

Mistakes on the attacking side

The commonest one is jumping first: a palcorner check against a centre Advisor just loses the Horse. The second is sacrificing without counting. If the General has a free point after the recapture, the Horse check is only a check and you are a Chariot down. The third is a blocked leg, so before you give up a Chariot, make sure nothing, yours or Black's, stands on the trough point next to your Horse.

Practise the hook

Set up both positions and play them through as Red, then as Black, until the recapture feels as forced to you as it does to the engine. After that, look for sacrifices that pull a centre Advisor away among the 5,000 engine-proven mate puzzles in XiangqiPlay's free puzzle library.