Questions about the cannon

炮 What counts as a screen for a cannon?Any single piece of either colour, of any type, standing between the cannon and its target. Exactly one is required — no more, no fewer. 炮 Why can't a lone cannon checkmate?Against a bare general in an empty palace there is nothing to jump over, so a lone cannon cannot even give check, let alone mate. 炮 What is the Central Cannon in xiangqi?The Central Cannon is 炮二平五, moving a cannon to the central file to attack the opposing general through the central soldiers. 炮 How do you defend against a cannon in xiangqi?Remove the screen, add a second one, block the line, or capture the cannon. Removing the screen is the answer most players overlook. 炮 What is 馬後炮 (horse behind cannon)?馬後炮 is the classic mate: a horse in front of the general with a cannon behind it on the same line, using the horse as its screen. 炮 What is 重炮 (double cannon)?重炮 is two cannons stacked on the same file as the general, with the front one acting as the rear one's screen. 炮 Can a cannon move without a screen?Yes. Moving requires a completely clear line — exactly like a chariot. Only capturing needs a screen. 炮 How should I use my cannons in the opening?Put one on a line that matters — usually the central file — and avoid moving either of them three times before your chariots have moved once. 炮 Why do cannons get weaker in the endgame?Because a cannon needs a screen to capture, and every trade removes a potential screen. An empty board gives a cannon nothing to work with. 炮 How do a chariot and cannon work together?The chariot opens and controls lines while the cannon fires across screens on them. Together they are the standard attacking pair against the palace. 炮 What is a cannon on the bottom rank called, and is it strong?A cannon dropped to the opponent's back rank (沉底炮) attacks along the rank behind the palace and is a standard attacking device. 炮 Does putting a piece in the way stop a cannon?It depends on the count. Adding a piece to an empty line switches the cannon on; adding one to a line that already has a screen switches it off. 炮 What is a hollow cannon (空頭炮)?空頭炮 is a cannon on the general's file with the line completely clear between them — a powerful positional threat, not an immediate check. 炮 Can you trap a cannon in xiangqi?Yes, though less often than a horse. A cannon cannot go around obstructions, so one deep in enemy territory can be cut off and won. 炮 Cannon or chariot — which is better?The chariot, clearly. It is worth about 9 against the cannon's 4.5, because it captures along any clear line with no screen required. 炮 What is the cannon called in Chinese — 炮 or 砲?Both are used and both mean cannon. 砲 has the stone radical, from siege engines that threw rocks; 炮 has the fire radical, from gunpowder. 炮 Why do chess players struggle with the cannon?Because it inverts the chess instinct: an open line means no attack, and blocking a line can create one instead of stopping it. 炮 Can a cannon pin a piece in xiangqi?Yes, but it takes two pieces between the cannon and its target, not one: then neither may leave the line, because that would leave the other as the screen. 炮 Should I keep both cannons or trade one?Keep both while the board is full, especially if you are attacking — two cannons make 重炮 possible. Trade one heading into an endgame. 炮 How do I stop missing cannon threats?Scan every line where a cannon faces your general or a valuable piece and count the pieces in between. Two seconds per cannon, every move. 炮 Can a cannon defend a piece in xiangqi?Yes, but only across a screen, the same way it attacks. A cannon defends a piece by being able to recapture on that point through exactly one piece in between. 炮 What is a cannon fork in xiangqi?A cannon fork is a single cannon move that creates two capture threats at once, typically by landing on a line where two different pieces each sit one screen away. 炮 How many cannons does each side start with in xiangqi?Two per side, placed on the third rank directly in front of the horses, with a completely open line across the board from the very first move. 炮 What is a cannon sacrifice in xiangqi?Giving up a cannon deliberately to open a line, remove a defender, or force the enemy general into a mating net, in exchange for a decisive follow-up attack. 炮 How do two cannons attack on different files in xiangqi?Rather than stacking on one file, two cannons can split across two files, each threatening a separate point near the palace so the defender cannot answer both. 炮 How does a cannon behave differently in the middlegame?At its strongest: plenty of pieces still on the board to act as screens, and enough of them are still mobile enough to create shifting, hard-to-track threats. 炮 Why do players avoid trading cannons too early in xiangqi?Because early on a cannon is close to its peak value, with plenty of screens available. Trading it off before it has done any work gives up that potential for nothing. 炮 How do you know if a cannon is good or bad in a given position?Count its available screens and its actual targets, not just its raw mobility. A cannon with no useful screen anywhere on its lines is doing almost nothing, whatever it looks like. 炮 Can a cannon attack two pieces at the same time in xiangqi?Yes, if two of its lines each already have a single screen with an enemy piece beyond it. That double threat is the basis of the cannon fork. 炮 Can a cannon be used to defend the palace in xiangqi?To a limited degree. A cannon aimed down a file the enemy wants can discourage its use, but it cannot occupy palace points the way advisors and elephants do. 炮 How much stronger is a cannon battery than a single cannon?Considerably more than double, because a battery removes the single-screen dependency: the front cannon supplies the rear one's screen automatically, every move. 炮 What is the fastest way to activate a cannon in xiangqi?Move it once, onto a line that already threatens something, typically the central file. A second cannon move before other pieces develop is usually wasted time. 炮 Can a cannon use the general as a screen?Yes. A cannon's screen can be any single piece of either colour, including a general or advisor. The rule does not distinguish piece types at all. 炮 How does a cannon work with a soldier as its screen?A soldier makes an excellent cannon screen because it is cheap to lose, hard to remove without cost, and often already advancing toward the enemy palace anyway. 炮 What is the same-direction cannons opening in xiangqi?順炮: Red opens with a central cannon and Black answers with a central cannon from the same side, giving a symmetrical and sharp opening. 炮 Does an open file help a cannon the way it helps a chariot?Not automatically. A chariot wants a clear line to attack down; a cannon usually wants a line with exactly one piece on it, so an open file can leave a cannon with nothing to jump. 炮 Can a cannon move along ranks as well as files?Yes. A cannon moves and captures along any clear rank or file, in any of the four straight directions, exactly like a chariot when it is simply moving without capturing. 炮 Can a cannon cause a perpetual chase in xiangqi?Yes. A cannon that renews a threat on the same undefended piece on every move while the position repeats is chasing it, and the chasing side must vary or lose. 炮 How many points can a cannon reach from the center of the board?Seventeen points on a completely empty board, from the centre or anywhere else: eight along its rank and nine along its file, since the board is nine files wide and ten ranks tall. 炮 Should you trade a cannon for a horse in xiangqi?It depends on the position. The two are close in value, so the decision usually turns on which piece your remaining army can support better, not on the trade being clearly good or bad. 炮 How do you reposition a cannon without losing its screen?Move the cannon along a different line than the one holding its screen, or shift it to a new file where a new screen is already waiting, rather than disturbing the piece it depends on. 炮 Can a cannon stop an enemy chariot?Not by blocking its line the way another piece would; a cannon defends by threatening to capture the chariot itself, or by controlling the specific point it wants to land on. 炮 Can a cannon give perpetual check in xiangqi?Yes. A cannon can check by moving or by gaining a screen, and if every move of a repeating cycle checks, the checking side must vary or lose. 炮 Can you win material by attacking a cannon's screen?Sometimes. If the screen is an undefended piece the cannon's own side needs, threatening or capturing it can both win material and switch the cannon's threat off in the same move. 炮 Can a pinned piece still act as a cannon's screen?Yes. A pinned piece is limited in where it can move, but a cannon's screen only needs to occupy the point in between, and being pinned does not stop it from doing that job. 炮 What is the technique for cannon and advisor versus a bare general?Bring the advisor to a point that serves as the cannon's screen, then use the cannon to cover the general's escape points and finish with a screened check. 炮 How does a cannon fare against two horses in xiangqi?Poorly on its own. Two horses coordinate to cover each other's blocked legs and can outmanoeuvre a single cannon, which needs a screen the horses can simply avoid supplying. 炮 Can a cannon battery form on a rank instead of a file?Yes. The screen mechanism works identically along a rank, so two cannons can stack sideways and threaten along it exactly as they would down a file. 炮 How many moves does it typically take a cannon to reach the enemy palace?Often just one or two, since the starting position hands both cannons a clear central line from move one. Reaching a useful attacking square is faster for a cannon than for almost any other piece. 炮 Can a cannon help defend against a horse fork?Sometimes, by threatening the forking horse itself across a screen, or by removing a piece that would block the horse's escape once it has forked you. 炮 How does a cannon perform in an endgame with only soldiers left?Reasonably well, since soldiers make cheap, expendable screens the opponent rarely wants to spend a move capturing, keeping the cannon's threats alive even as other screens disappear. 炮 Is it better to commit one cannon early or wait for both to coordinate?Commit one early to create an immediate threat and force a response; hold the second back until it has a specific job, since two cannons developed without purpose waste far more time than one used promptly. 炮 Can two cannons share the same screen piece at once?Yes. A single piece can serve as the screen for more than one cannon simultaneously, including cannons of opposite colours facing each other along the same line. 炮 Can a cannon's screen be sitting right next to it, or does it need to be further along the line?Yes. The screen can be the very next point on the line, immediately adjacent to the cannon, or anywhere further along it; distance from the cannon itself makes no difference to the rule. 炮 Does a cannon gain value by crossing the river, the way a soldier does?Not directly. A cannon's reach and screen mechanics work identically on either side of the river, so crossing changes its targets rather than its underlying power the way it does for a soldier. 炮 Is the cannon considered a major piece like the chariot, or grouped with the minor pieces?Chinese commentary groups the chariot, horse and cannon together as the big pieces (大子). It is a convention, not a rule, and by value the cannon sits close to the horse. 炮 Is it ever worth trading a cannon for an elephant or advisor to break open the enemy defence?Sometimes, when the elephant or advisor is the one piece holding a mating attack together, since removing it can be worth far more than the material given up. 炮 Can a cannon ever capture a piece sitting on a point immediately next to it?No. A cannon always needs exactly one screen between itself and its target, so the closest point it can ever capture on is two points away, never directly adjacent. 炮 Can a soldier that hasn't crossed the river yet serve as a cannon's screen just as well as one that has?Yes. A screen's status has no bearing on whether it can serve as one; an uncrossed soldier blocks and screens exactly like a crossed one, or any other piece on the board. 炮 What is the palace corner cannon (士角炮) opening?The palace corner cannon moves a cannon one file toward the centre, onto the rib at the palace's front corner, instead of all the way to the centre. 炮 What is a river-patrolling cannon (巡河炮)?巡河炮 is a cannon advanced two points to its own river bank, where it can slide along the rank to defend or switch wings.