Identify the three parts of the tuna

• Note that the tuna comes from Japan and has three parts: chi (blood part), akami (lean part) and chutoro (fattier part).

Remove the chi (blood) part

• Cut away the chi, the blood part, which has a stronger taste.
• Set it aside, as it is better suited for cooking tuna steaks.

Separate the akami (lean) part

• Cut out the lean akami part, which is more tasty.
• Trim off the harami skin, which is harder.

Cut the akami into saku blocks

• Cut the lean tuna into saku blocks so it is easy to prepare for sashimi.
• Keep the trimmings for other uses.

Slice the sashimi

• Cut each saku straight, into pieces about one finger and a half in size.
• For each sashimi soba portion, use two pieces of akami and mix in some chutoro.

Store the tuna

• Decide the position of each block and store it properly.

Cook the chi part as tuna steaks

• Cook the blood part in a pan as tuna steaks.

Assemble the sashimi soba

• Serve the sliced akami and chutoro sashimi alongside the buckwheat soba noodles.
• Enjoy the akami for its gummy texture and the fatty parts for their texture.