Sawing a woman in half is a famous stage magic trick, first performed by P.T. Selbit in 1921. This illusion is part of the cut and restore family of illusions, which includes the cut and restore rope trick.
The effect
A woman lays down in a large, horizontal box, from which her feet and head protrude. The magician appears to saw her in two with a large saw. The two halves are separated, and yet the assistant is fine. She usually wiggles her toes to demonstrate they are not fake. Sometimes the sides of the box are opened, revealing the assistant's arms and legs. Some magicians have performed this trick without a box, others have sawn their assistants into more than two pieces. In the end, the two halves are rejoined, and the woman exits the box unharmed.
One variation of this trick is the 'double sawing' in which two assistants (usually in different colored costumes, of different races, or even different genders) are sawn and restored with the other's lower half.
See also
