hahaha cold rice is not must. my mom cooks with warm rice and it comes out perfect. it is matter of quality of rice. so yeah, if you are using japonica rice that is not good quality or cooked right, it will be all mushy when you cook it. If that is the case, cook rice little bit undone than you normally would. Soy sauce, is big no no??? you don't even know!! just pour little bit from the side and it gives nice flavor. Don't use too much of it tho.