Why is my sushi rice too sticky? I'm on a quest of learning how to prepare a more than edible sushi. I figured that with enough practice I can achieve the goal of being able to make sushi. The most important part of sushi as I see it is the rice, and that's where I'm not really sure what I am doing wrong.

Although I'm making progress with the rice, it still comes out wrong, too sticky - ie not brittle enough - after it sticks it very hard to break, becomes a sort of Plasticine.

My question is, what variables should I try to change in order to make it less Plasticine? Cook it less, put less oil, boil it less time, let it steam on low fire more etc... Or more generally put, which parameters influence the texture of the rice and how?
In general, the stickiness of rice can be reduced by removing some of the starch by pre-soaking and/or washing the rice.  For sushi rice, chewiness can be increased by reducing the amount of cooking water.

For what do you use oil?  I don't believe that is a traditional ingredient in sushi rice.