In order to study the initiation of detonation waves, the time dependent one‐dimensional hydrodynamic equations have been numerically integrated for several initial conditions. In all the cases treated, the hydrodynamic motion and the release of chemical energy are practically independent as a consequence of the extreme temperature sensitivity of the reaction rate. At first the chemical energy is released so slowly that it has no effect on the hydrodynamic motion. Thereafter the reaction proceeds so rapidly that the burning is not influenced by the hydrodynamic motion. A simple criterion is established to determine whether or not detonation will result from given initial conditions of pressure and temperature. This criterion is applied to determine how the detonability depends upon the duration of the initial pressure pulse and upon the initial temperature distribution.