Laws of Cricket 1947 Code - Law 38
The Striker is out "Hit wicket" - If in playing at the ball he hit down his wicket with his bat or any part of his person.
Notes on Law 38
1. The striker is "Out" under this Law if:
a. In making a second stroke to keep the ball out of his wicket he hits it down.
b. While playing at the ball, but not otherwise, his wicket is broken by his cap or hat falling, or by part of his bat.
2. A batsman is not out for breaking the wicket with his bat or person while in the act of running.
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