(Sorry, but that fish is just too long for the screen!)
Scabbard Fish or “Tachiuo” (太刀魚/Great Sword Fish in Japanese), a very popular in Japan in spite of its great length is usually caught in Summer in Japan but also appears in Winter in Shizuoka Prefcture.
As other fish it owns other names: Tachi (not in Hokkaido, where the word means “whiting”!), Shirada and Tachinouo.
It is mainly caught off Wakayama, Ehime and Oita Prefectures, although it is also caught in Suruga Bay off Shizuoka Prefecture
It is both caught by line or net.
In 1999, 37,000 tonnes were caught, but it fell to 23,000 tonnes in 2000.
It is also imported from Kore and China, although their fish is slightly different from the Japanese variety. More than half of imported fish are eaten west of Kansai.
It is fish than can be eaten raw as nigiri.
I personally prefer it “aburi” (slightly grilled) with a dash of ponzu and some momijioroshi (grated daikon with chili pepper) as above served at Sushi Ko Restaurant.
Some time ago I ate it at Oboro No Tsuki Restaurant (now defunct) as above:
They first put a double layer of sushi rice interspaced with shiso leaves (perilla) in a box for “oshi zushi” (pressed sushi), then top it with thick fillets (the fish is actually quite thin) and press the whole.
Next they slightly grill the top (“aburi”), take it out of the box and cut it to size.
Quite tasty and appetizing-looking!