Oshizushi — Osaka's Pressed Sushi Tradition (押し寿司)

Ingredients

• For the sushi rice
• 400 g Japanese short-grain rice, cooked and seasoned with sushi vinegar
• 60 ml rice vinegar, combined with sugar and salt for sushi-zu seasoning
• 2 tsp sugar, for sushi-zu
• 1 tsp fine salt, for sushi-zu
• For the battera topping
• 2 saba (mackerel) fillets, lightly cured in salt and rice vinegar; skin-on, usukawa (silver skin membrane) intact
• 1 konbu sheet, cut to fit the mould; wiped clean
• For the mould
• 1 oshibako (wooden pressing mould), hinoki or cedar; soaked in water and wiped with rice vinegar before use

Method

1. 1
   Soak the oshibako mould in cold water for several minutes, then wipe all interior surfaces with rice vinegar. This prevents adhesion and seasons the wood. The mould is ready when it feels damp but holds no standing water.
2. 2
   Cure the saba fillets: salt generously, rest for 30–60 minutes, then submerge in rice vinegar for a further 30 minutes. Remove, pat dry, and peel away the usukawa — the thin silver-skin membrane — to expose the fish's shimmering geometric pattern beneath. The surface should appear translucent and lightly opaque, not raw.
3. 3
   Season the cooked rice with the sushi-zu (vinegar, sugar, salt combined). Fold with a flat paddle — do not stir — until the rice is glossy and each grain is distinct. The rice is ready when it is just warm to the touch and no steam rises.
4. 4
   Lay the cured saba flesh-side down in the prepared mould. Place the konbu sheet directly over the fish — the glutamate in the konbu will transfer into both the fish surface and the rice layer above it during pressing. The konbu should lie flat with no overlapping edges.
5. 5
   Press a 2 cm layer of seasoned rice evenly over the konbu. Fit the wooden lid and apply firm, even hand compression. This is where the dish lives or dies: pressure must be sufficient for the layers to adhere and the block to hold its shape when cut, but not so great that the rice is compacted into a dense, airless mass — the grains must remain individually perceptible under light finger pressure through the lid.
6. 6
   Refrigerate the mould, lid weight on, for 30–60 minutes. The block is set when the exterior rice layer feels firm and cool, and the mould can be handled without the contents shifting.
7. 7
   Invert the mould onto a board. Lift away the mould to unmould the block — the saba now faces upward, its shimmering pattern revealed. With a wet, sharp knife, cut the block into portions using a single decisive stroke per cut. Sawing tears the compressed structure. Each piece should show clean-edged layers of fish, konbu, and rice with no crumbling at the cut faces.