At Sushiro, the sale of "rich sea urchin wrapping" has started for a limited time. One of the "100 Yen PROJECT of Good Neta from the Seas of the World" that started in 2016 to dig up ingredients from all over the world and use them as neta.
Sea urchin has a rich and deep umami, sweetness, and melting mellowness that goes well with the rice. It seems to be a new item just caught this season.
The price is 100 yen (excluding tax). Some stores in Tokyo have different items and prices. Also, it is not handled by "Sushiro Konomi". You can take it home, in which case you will have one warship.