Stealth kills, and indeed combat in general, work in exactly the same way as in the other Tenchu games. A small icon in the bottom right hand corner of the screen alerts you to the status of guards around you - indicating whether they are aware of you or not. How careful you are in using this dictates whether you can slide in for the stealth kill, or engage in a very basic combat system. Stealth kills can be very glitchy though, and this removes some of the satisfaction gained by performing them. Various tools that you can select at the start of each stage can be used to manipulate and remove guards as well, such as poisoned rice and throwing stars.
