Kayaku -Jutsu is a term used when designation for that chapter of fire and explosives are required. This study of secret technicques was used when the ninja needed the fire for escape, distract or some other discipline. The secret of this was the alchemy, the ninjas had to expand their mind to get sucess. The used the nature, the earth (chi), for develop Ka (fire). He prepared black podwer and inserted it on eggs, or some other devices where to carry it and get it quickly when it was needeed. So, u have first to try about if u can adquired black power, after that insterted on small eggs and put some lighter little rocks or magnesium, so when its droped hardly it explored,. expanding by this way the smoke and u can hide, run, escape, or attack ur opponent (but remember: the ninja never attacked his enemy unles it was necesary...)