The Osaka style sushi is commonly called Oshizushi, meaning pressed sushi. In comparison with nigiri or sushi rolls, it is easier to make because you hardly need any skills in the process of making sushi. You simply put ingredients and sushi rice in the mould, put a lid and press it several time. The result is a beautifully shaped sushi.
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A oshizushihako (pressed sushi box) is a box or mould used to make oshizushi (pressed sushi). The box is traditionally made from wood, but nowadays often made from plastic. The box can be taken apart into three parts, a bottom part, the rectangular walls, and a top part. Before use, the wooden box should be put in water so that the rice sticks less to the box. The bottom part and the top part can be covered with a layer of plastic foil for easier cleaning. The bottom part and the walls are assembled before the rice and the topping is added. Next, the top part is used to press onto the sushi, hence the name pressed sushi. For disassembly, the rectangular walls are pulled up while the top part still presses onto the sushi. After removing the top part the sushi is cut and can be served.

A variant of the oshizushihako has half cylindrical shapes cut from the thicker top and bottom parts so that the sushi is pressed in a cylindrical shape.