Shurikenjutsu is effective only if you have enough distance between you and the attacker.
But if is the attacker very close to You, You don´t have the time or distance to use Shurikens.
Shoken jutsu uses shurikens as a hand weapon. In Shoken jutsu is used shuriken for stabbing, slashing or cutting the attacker just as we do it for example with a knife. Movements of Shoken jutsu are based on the movements of Kusari Fundo and both of which come from sword techniques.
In Meifu Shinkage Ryu we use for Shoken jutsu particularly special weapon which we call Shoken and which is similar to modern boxer.
