This video, titled "Catching Flatfish for 50 Years, Zabuton for 15, but There's Still More to Come! Zabuton Flounder Ebisutei, Hirado" (ヒラメをさばいて50年。ざぶとんは15年。まだまだです。　ざぶとんヒラメ＜さばき編＞　平戸・エビス亭), was released by "99チャンネル 99chtv."
Flounder, with its mild flavor, is a top-quality ingredient when used for sashimi.
In this video they clean a huge flounder, which is big even compared to other large flounder.

"Zabuton" flounder as they're called in Japanese refer to flounder between 70 and 90 cm in length and that weigh over 4 kg.
Its size and weight make it a difficult fish to process fresh.
The owner of Ebisutei in Hirado, Nagasaki, is the one processesing the fish.
Japan's techniques for handling fish are among the best in the world in terms of speed and maintaining freshness.
Look at the skill of the owner as he handles the flounder!