Lying Trough Horse in Xiangqi: The 卧槽马 Checkmate

What the name means, and what else it is called

卧 means to lie down and 槽 is a trough or manger, so the literal picture is a Horse lying at the feeding trough, settled right beside the enemy palace. English translations vary. You will see lying trough horse, horse in the trough, and on some sites elbow horse. Because the labels differ, check where the Horse actually stands on a diagram instead of trusting the name.

The geometry is simple. Seen from Red's side, the two trough points are on Black's second rank, on the third file from each edge. A Horse there reaches the General's home point in one leap, and its leg is the point next to it on the palace's side edge. Through that same leg it also hits the middle of the palace's front edge. Using the point on its outer side as a leg, it reaches the corner of the back rank, which is where Black's Chariot starts the game.

The basic mate: trough Horse plus rib-file Chariot

Set this up. Black's General is on its home point. One Black Advisor sits in the palace centre and the other on the back corner on Red's right. Red has a Chariot on the left rib file, the file running along the left edge of the palace, standing on Red's side of the river on the rank nearest the river, with nothing in front of it all the way to Black's back rank. A Red Horse stands on Black's soldier row on the file of Black's right-hand Horse, and the Red General is at home. Red to move.

The Horse leaps into the right-hand trough, and Black is mated. Black's own Advisors now work against it: one blocks the palace centre, the other blocks the right back corner, and the only free point, the left back corner, is covered by the Chariot. Nothing can capture the Horse, since Advisors and Elephants can never reach a trough point, and nothing can occupy its leg. XiangqiPlay's rules engine confirms that Black has no legal reply.

Now take the Chariot off the board and replay the jump. It is still check, but the General simply steps into the empty left corner. That one comparison is the heart of the pattern. The trough Horse attacks, and a partner has to close the rib file on the far side.

Everything mirrors to the other wing. With the Advisors reversed, the Horse uses the left-hand trough and the Chariot takes the right rib file.

Check, and the Chariot falls

The trough has a second, nastier use early in a game. Picture Black with the General, both Advisors and both Elephants still on their starting points, the right-hand Horse and Chariot also at home, and the central Soldier in place. Red has its central Soldier and General at home and a Horse on Black's soldier row, on the file of that right-hand Black Horse. The Red Horse jumps into the trough: check to the General, and an attack on the Chariot in the corner at the same time.

Black's only legal reply is to lift the General into the palace centre, and then the Horse takes the Chariot, with nothing able to take it back. Why nothing better? The Elephant standing at home beside Black's Horse blocks that Horse's leg, so it cannot hop onto the point that would hobble the checking Horse.

Remove that Elephant and Black gains a second option: the Horse can jump to the middle of the palace's right edge and block the check at the leg. The Chariot is still lost, though, because the Red Horse attacks the corner through a different leg. This is why Chinese texts link 卧槽马 with the phrase 将军抽车, check and pick off the Chariot.

Getting there in real games

A Horse usually reaches the trough from Black's soldier row, from one of the files on either side of the trough file, or sideways from Black's third rank, either from the board's edge or from the middle of the palace's front edge. Each approach has its own leg point, so before you plan the route, make sure the point next to your Horse in the direction it travels furthest is empty.

The attack is strongest when Black's Advisors stand as they did in the mate above, one in the centre and one on the back corner on the trough side, because together they fill two of the General's three exits. Then you need only one more piece controlling the back corner on the other side. A Chariot on that rib file is the usual partner.

Mind the waiting time. A Horse parked on Black's soldier row, one leap from the trough, is visible to everyone, and a defender who sees it will block the leg or bring a piece over. When the path is clear and the partner is in place, jump at once.

Defending against the trough

Because the trough lies outside the palace, Advisors and Elephants can never guard it, and a Horse on its starting point cannot jump there either. Only a Chariot, a Cannon, or a Horse that has already moved can cover the point, so when an enemy Horse is circling, keep one of them within reach.

The leg is the other target. A piece on the middle point of the palace's side edge, next to the trough, stops the check before it starts. In the Chariot fork above, that was exactly the resource Black found once the Elephant was gone.

Most important of all is the Chariot's home point. If your Chariot is still in the corner and an enemy Horse is one leap from the trough, move the Chariot or cover the trough now. A single slow move can cost the piece.

Where attackers go wrong

The most common slip is jumping in with no partner on the far rib file. The check looks forcing, the General steps across, and the Horse has spent several moves getting there for one check.

The second is ignoring the defender's counterplay. A Horse that needs three or four moves to reach Black's second rank gives the opponent time, so count their threats before committing, especially checks against your own General.

The third is forgetting that the leg can be blocked from outside the palace as well as from inside it. A defending Horse, Cannon or Chariot that can reach the palace's side edge in one move is a defender, even when it looks far away.

Put it on the board

Set up the two positions from this article, play the Horse jump, then try to defend them as Black. After that, XiangqiPlay's free library of 5,000 engine-proven mate puzzles will test whether you spot the trough under pressure, and with a free account you can try it against the computer at any of its eight levels (Easy to God).