The basic ingredient for any good sushi starts and ends with the rice. Sushi rice can be bought in most supermarkets and is a short-grain Japanese rice, which must be cooled before use as it will turn sticky and be difficult to work with. It is really important to make sure you wash the rice under cold water until the water is clear; this ensures the perfect sushi rice. This recipe makes enough for 24 pieces. Sushi seasoning can be made at home quite easily, but bottles of pre-mixed sushi seasoning can also be purchased in good supermarkets and Asian shops.