@guest: I typed wrongly. Is 12960jpy per pax. After tax and ocha came up to 14000+ JPY per pax.
@Saito-san: Sure thing! Really enjoyed the restaurants you recommended. Will be going to Tokyo again in Sept for another sushi-hunt, with reservations at hakkoku, namba hibiya and inomata.
Will update again!
If you're looking for high-quality ingredients and sushi, then I think it's safe to pick Hakkoku. (Hashiguchi's selling points are that it's easy to get a reservation and that it has good value for the price.)
I would say the order is "羽立生うに" (brand) from 羽立水産 (Hadate company), followed by the "生うに" from 東沢水産 (Higashizawa), then the two from 橘水産 (Tachibana), "生うに" and "まるひろの生うに."
Recently the "生うに" from ダイセン水産 (Daisen) has also been popular.
Where possible, I think it is better to make a reservation in advance of your visit. However, as we do not accept reservations for Sushi Ishijima, please expect some waiting time on the day of your visit.