Tiger Strikes

Tiger Strikes is a passive monk ability, learned at level 10. It has a 10% chance to trigger while using a two-handed weapon, and a 5% chance to trigger while dual wielding.

Mists of Pandaria
Tiger Strikes originated in Patch 5.0.4 as a passive ability for Windwalker monks that would had an 8% chance on each attack to proc a 50% attack speed buff and 4 extra attacks. The ability remained unchanged throughout Mists of Pandaria and was a minor tool in the Windwalker kit.

Warlords of Draenor
In Patch 6.0.2, Warlords of Draenor made the ability available to all monk specializations (except Mistweavers in Stance of the Wise Serpent) and redesigned to use the new multistrike stat. In this version, the ability had an 8% chance (5% while dual-wielding) to proc off both attacks and multistrikes, and would give the monk a 25% multistrike buff for 8 seconds.

Patch 6.2 increased the multistrike buff to 35% but also changed the ability so it would only proc off of attacks--multistirkes could no longer trigger the effect. This change primarily benefited Brewmaster monks (who did not ordinarily focus on multistrike) by increasing their self-healing potential through Gift of the Ox. It had a more negative effect on Mistweavers and Windwalkers, which due to their emphasis on increasing their multistrike anyway would not gain additional procs and uptime of the effect through their multistrikes.