Each side has two innings, taken alternately, except in the case provided for in Law 14. The choice of innings shall be decided by tossing on the field of play.

NOTES ON LAW 13

1. The captains should toss for innings not later than 15 minutes before the time agreed upon for play to start. The winner of the toss may not alter his decision to bat or field once it has been notified to the opposing captain.
2. This Law also governs a One-day match in which play continues after the completion of the first innings of both sides. (See also Law 22.)

Reproduction of the Laws of Cricket is by kind permission of Marylebone Cricket Club