Masu-zushi (鱒寿司, Toyama pressed trout)

Masu-zushi looks like a small ceremony: a round bundle of bamboo leaves, pale trout over vinegared rice, and a string pulled tight to cut it cleanly. You may think the box is doing some secret work. It isn't. The real work is choosing good fish, curing it plainly, and pressing it with enough patience for fish, rice, and leaf to become one dish.

Sourcing comes first. Traditional Toyama masu-zushi belongs to sakuramasu in spring, when the fish is at its shun, its prime. At home, use a salmonid sold specifically for raw eating and properly frozen for parasite control. Salt and vinegar can firm good fish and sharpen its flavor, but they don't rescue doubtful fish. If it smells strong or looks tired, change the dish. Nothing hidden, especially here.

The detail that decides it is the cure. Salt draws out water and tightens the flesh; vinegar gives the clean sour edge that answers the rice. Pressing is gentler than it sounds. Too much weight turns rice into paste, too little leaves the layers strangers. We want a round that holds its shape, with each grain still visible and the trout sitting smooth on top.

This is picnic food with manners. It travels wrapped, rests well, and cuts with a string because a knife likes to drag the fish along with it. Pull the string taut and let it do the work. A neat wedge opens, pink over white, green leaf folded back. Leave it room.