What is capturing is compulsory in Draughts (International)?

Verdict

Capture is possible both forwards and backwards, counts as one complete move, and you may never capture your own pieces (4.1); When a man meets an opponent's piece diagonally with a free square behind it, he is obliged to jump it and occupy that square; the jumped piece is removed (4.2); A king m...

Why people argue about this

People often assume that capturing is optional in Draughts International, forgetting that it's a compulsory move when you can jump your opponent’s piece. They misunderstand that once you have the option to capture (by jumping over an enemy piece), you must do so as part of your mandatory move, even if doing so would leave your king unprotected on the side or corner squares.

Send this to your friend — argument over.

4. Gameplay

Moving a Man

A man moves forwards along a diagonal to an empty square of the next row (3.4)
A move is finished when the player has released the piece (3.10)
Touching one of your own playable pieces obliges you to play it, provided a legal move exists (3.11)
Until the piece is released you may still place it on another free square (3.12)
To tidy pieces without moving them, announce "I adjust" (or j'adoube) clearly and beforehand (3.13)
Touching or adjusting any piece when it is not your move is incorrect (3.14)

Kings

A king is a man that reaches and stops on a square of the promotion line nearest the opponent, and is crowned with a man of the same colour (3.5)
Either player may crown the man; if the opponent does not, crowning it is part of the mover's own move, and failing to do so is an irregular move (3.6)
A promoted man is a king even while uncrowned, and either player may crown it later — but playing with an uncrowned king is an irregular move (3.7)
A newly crowned king cannot move until the opponent has played (3.8)
A king moves forwards and backwards along its diagonal over successive free squares, and may come to rest on a distant free square (3.9)

Capturing Is Compulsory

Capture is possible both forwards and backwards, counts as one complete move, and you may never capture your own pieces (4.1)
When a man meets an opponent's piece diagonally with a free square behind it, he is obliged to jump it and occupy that square; the jumped piece is removed (4.2)
A king meeting an opponent's piece on its diagonal — close or distant — with one or more empty squares behind it is obliged to jump and may land on any free square beyond (4.3)
The capture of the largest number of pieces has priority and is obligatory; a king carries no priority and counts as one piece, exactly like a man (4.13)
Between captures of equal value the player chooses freely, with a man or a king (4.14)

Multiple Captures

A man that meets a further capturable piece during a capture must jump that second piece, and a third, and so on (4.5)
A king may turn a corner onto a perpendicular diagonal to continue a capture, finishing on a square of choice beyond the last piece taken (4.6)
It is forbidden to jump your own pieces during a multiple capture (4.7)
You may pass over the same empty square more than once, but never over the same enemy piece twice (4.8)
A man that merely passes over the promotion row mid-capture and ends elsewhere remains a man (4.15, confirming 3.5)

Executing a Capture Cleanly

A capture must be clearly indicated and executed in order; absence of clear indication is incorrect and the opponent may request rectification (4.4)
The move and the removal of captured pieces must be done with one and the same hand — using two hands is incorrect (4.4)
Indicate a multiple capture by putting the piece down on the empty square after each jump (4.9)
Captured pieces are lifted only after the capture is complete, in ascending or descending order of the capture, without stopping (4.11)
The capture is finished when all captured pieces have been lifted (4.4); removal is finished when the player has taken all of them or has clearly stopped (4.12)
When a man captures a single man, it is permitted to remove the opponent's man first and then jump (4.16)

Irregularities

On any listed irregularity the opponent chooses whether it is rectified or allowed to stand (5.4)
The list covers playing two moves in a row, moving irregularly, touching one piece and moving another, taking back a move, moving the opponent's piece, and playing a quiet move when a capture was available (5.4.1–5.4.6)
It also covers capturing the wrong number of pieces, stopping mid-capture, lifting pieces irregularly, removing too few, removing unjumped pieces, and removing one's own pieces (5.4.8–5.4.14)
Promoting without crowning, playing an uncrowned king, and using two hands are each irregularities (5.4.15, 5.4.16, 5.4.17)
An accidental disturbance of the position is not an irregularity, provided it is noticed at the same time (5.5)
Playing a move after the opponent's irregularity accepts it — rectification can no longer be obtained (5.7)
Partial rectification of an irregularity or a refusal cannot be tolerated (5.8)
A player refusing to comply with the official rules can be forced to comply by the opponent (5.6)

4. Gameplay

Moving a Man

A man moves forwards along a diagonal to an empty square of the next row (3.4)

A move is finished when the player has released the piece (3.10)

Touching one of your own playable pieces obliges you to play it, provided a legal move exists (3.11)

Until the piece is released you may still place it on another free square (3.12)

To tidy pieces without moving them, announce "I adjust" (or j'adoube) clearly and beforehand (3.13)

Touching or adjusting any piece when it is not your move is incorrect (3.14)

Kings

A king is a man that reaches and stops on a square of the promotion line nearest the opponent, and is crowned with a man of the same colour (3.5)

Either player may crown the man; if the opponent does not, crowning it is part of the mover's own move, and failing to do so is an irregular move (3.6)

A promoted man is a king even while uncrowned, and either player may crown it later — but playing with an uncrowned king is an irregular move (3.7)

A newly crowned king cannot move until the opponent has played (3.8)

A king moves forwards and backwards along its diagonal over successive free squares, and may come to rest on a distant free square (3.9)

Capturing Is Compulsory

Capture is possible both forwards and backwards, counts as one complete move, and you may never capture your own pieces (4.1)

When a man meets an opponent's piece diagonally with a free square behind it, he is obliged to jump it and occupy that square; the jumped piece is removed (4.2)

A king meeting an opponent's piece on its diagonal — close or distant — with one or more empty squares behind it is obliged to jump and may land on any free square beyond (4.3)

The capture of the largest number of pieces has priority and is obligatory; a king carries no priority and counts as one piece, exactly like a man (4.13)

Between captures of equal value the player chooses freely, with a man or a king (4.14)

Multiple Captures

A man that meets a further capturable piece during a capture must jump that second piece, and a third, and so on (4.5)

A king may turn a corner onto a perpendicular diagonal to continue a capture, finishing on a square of choice beyond the last piece taken (4.6)

It is forbidden to jump your own pieces during a multiple capture (4.7)

You may pass over the same empty square more than once, but never over the same enemy piece twice (4.8)

A man that merely passes over the promotion row mid-capture and ends elsewhere remains a man (4.15, confirming 3.5)

Executing a Capture Cleanly

A capture must be clearly indicated and executed in order; absence of clear indication is incorrect and the opponent may request rectification (4.4)

The move and the removal of captured pieces must be done with one and the same hand — using two hands is incorrect (4.4)

Indicate a multiple capture by putting the piece down on the empty square after each jump (4.9)

Captured pieces are lifted only after the capture is complete, in ascending or descending order of the capture, without stopping (4.11)

The capture is finished when all captured pieces have been lifted (4.4); removal is finished when the player has taken all of them or has clearly stopped (4.12)

When a man captures a single man, it is permitted to remove the opponent's man first and then jump (4.16)

Irregularities

On any listed irregularity the opponent chooses whether it is rectified or allowed to stand (5.4)

The list covers playing two moves in a row, moving irregularly, touching one piece and moving another, taking back a move, moving the opponent's piece, and playing a quiet move when a capture was available (5.4.1–5.4.6)

It also covers capturing the wrong number of pieces, stopping mid-capture, lifting pieces irregularly, removing too few, removing unjumped pieces, and removing one's own pieces (5.4.8–5.4.14)

Promoting without crowning, playing an uncrowned king, and using two hands are each irregularities (5.4.15, 5.4.16, 5.4.17)

An accidental disturbance of the position is not an irregularity, provided it is noticed at the same time (5.5)

Playing a move after the opponent's irregularity accepts it — rectification can no longer be obtained (5.7)

Partial rectification of an irregularity or a refusal cannot be tolerated (5.8)

A player refusing to comply with the official rules can be forced to comply by the opponent (5.6)

Capturing Is Compulsory