The Opposite-Direction Cannons

Cannons from opposite sides

Red's cannon comes to e2 from h2, and Black's comes to e7 from b7, so the two arrive from opposite sides of the board. Each cannon then attacks the other side's centre soldier over its own: Red's attacks e6 over e3, and Black's attacks e3 over e6. Like the same-direction cannons, the opening is known for this strong mutual attack.

Both openings are cannon-fight openings (斗炮局, doupaoju), in which Black's central cannon aims to balance Red's. The ECCO, a code list of xiangqi openings, puts both in its class D, with the opposite-direction cannons at D30 to D55.

The opening has three forms: the big opposite cannons (大逆手炮, da nishoupao), the small opposite cannons (小逆手炮, xiao nishoupao) and the half-way opposite cannons (半途列炮, bantu liepao). As Black, keep one warning in mind: if you copy Red move for move, Red gets the better game.

The course line, move by move

The walkthrough plays the line that Xiangqi Arena's opening course teaches. It starts with the two moves that define the opening, a computer engine continued it from there, and the board shows its first twelve moves, six for each side. As you step through it, keep an eye on the h-file and the b-file, where the chariots go to work.

From Red's second move to Black's fifth, the two sides bring out the same pieces in the same order. A horse goes to the g-file, a chariot to the h-file, a horse to the c-file and a chariot to the b-file. On the h-file and on the b-file, a chariot attacks a cannon, and the cannon's own chariot guards it. Red's chariot on h0 attacks Black's cannon on h7, and Black's chariot on b9 attacks Red's cannon on b2.

The pattern breaks on Red's sixth move. Red's chariot crosses the river to h6 and attacks the cannon on h7, and the cannon steps aside to i7. Now the chariots on h6 and h9 attack each other, and only Black's has a guard, the horse on g7. The second card below reaches the same standoff with fewer pieces out.

In the opening course, the lesson on this opening plays the line further than the twelve moves shown here. Its drill has you play Red's moves, and the board answers with Black's moves from the same line.

When does Black's cannon reach the centre?

The archive names three lines of the opposite-direction cannons, and they differ in when Black's cannon reaches the centre. In the third card, the big opposite cannons, Black plays 炮2平5 (C2=5) at once. In the second, it comes on Black's third move, after 马8进7 (H8+7) and 车9平8 (R9=8), which is the half-way form. In the first, it comes on Black's fourth move, after Black's other cannon has crossed the river to h3.

If you want the two central cannons facing each other from your first move, start with the big opposite cannons. If you prefer to bring out a horse and a chariot first, the other two cards keep the cannon back for a few moves. Each card shows how its line scored in the archive, so compare them before you choose.

What if Red takes the centre soldier?

The strength of this opening is that Black, the second player, can win the initiative. You can see it when Red's cannon takes the centre soldier early. Black blocks the check with 士6进5 (A6+5), then brings out the horse and the chariot first with 马8进7 (H8+7) and 车9平8 (R9=8). That turns the tempo round and puts Red's central cannon in difficulty.

The capture is a beginner's trap, in this opening and in the same-direction cannons. If Black answers correctly, it holds back the development and coordination of Red's pieces. Black gets a chariot out first, and with the centre soldier gone, Black's horses can occupy the centre.

The board below plays these moves. Red's 炮五进四 (C5+4) takes the soldier on e6 with check, because Black's own cannon on e7 is the screen between Red's cannon and the general. Black's 士6进5 (A6+5) puts a second piece on the file and blocks the check.

After Red's 马二进三 (H2+3), Black's 马8进7 (H8+7) attacks the cannon, which nothing guards, and the cannon retreats to e4 with 炮五退二 (C5-2). Black's chariot then comes to h9 with 车9平8 (R9=8), while both of Red's chariots are still at home.

The opening also has an old rule of its own, 列手炮，补士要牢 (lieshoupao, bushi yao lao): in the opposite-direction cannons, put the advisor firmly in place. The rule comes from the 全旨 (Quanzhi) section of the Ming manual 橘中秘 (Juzhongmi). On the board, the advisor comes to e8 on Black's second move, and that is the move that stops the check.

Common mistakes

Some players copy Red move for move as Black. Red moves first, so in a copied position Red always acts first and gets the better game. In the course line Black matches Red's development for four moves, but Red's chariot is the first piece across the river, to h6. Black then answers with a threat of its own: the cannon steps aside to i7, and Black's chariot on h9 attacks Red's chariot, which has no guard.

Another mistake is to press on with the attack while the general stays exposed. Both central cannons stand on the e-file, so Black's own cannon on e7 can become the screen for a check, as it does when Red's cannon takes e6. That is the danger behind the old rule of this opening: put the advisor firmly in place. On the board above, Black's 士6进5 (A6+5) blocks the check at once and keeps the general safe.

As Red, the mistake to avoid is grabbing the centre soldier early. 炮五进四 (C5+4) wins the soldier on e6 with check, but after 士6进5 (A6+5) and 马8进7 (H8+7) the cannon is attacked and retreats to e4. By the time Black's chariot reaches h9, the cannon has made three of Red's first four moves, and both of Red's chariots are still in their corners. A soldier is worth little this early, and every move you spend on it is a move your other pieces do not get.

The opposite-direction cannons in the archive

In the 1,129 games with the opposite-direction cannons, Red won 40%, Black won 26%, and 33% were drawn. Across all 29,164 games between human players in the archive, Red wins 37% and 36% end in a draw, so you can compare the opening with the average game. A game with this opening lasts 43 moves on average.

As Black, Chen Hanfeng has the best score with the opening, 42.6% from 34 games. On the Red side, Lü Qin played the most games against it, 25. You can look up both players in the archive and replay their games move by move.

In the classical manuals

Players have studied this opening for centuries. 橘中秘, the Ming manual by 朱晋桢 (Zhu Jinzhen), is known for its study of the central cannon. It is one of the two famous manuals named together as 橘梅 (jumei).

The other, 梅花谱 (Meihuapu) by 王再越 (Wang Zaiyue) of the Kangxi era, makes a special study of the opposite-direction cannons among other openings. One of its chapters, five games long, shows the first player's central cannon beating the opposite-direction cannons.

梅花谱 was not printed under the Qing. It circulated in handwritten copies until a lithographed edition appeared in 1917, followed by a printed edition in 1926.

To make the opening your own, step through the course line until you can say what each move is for. Then play it as Black in a few games against the computer. It will not win games by itself, but it gives Black an active answer to the central cannon.