Pop up cafe reservations

Hello,

My husband and I are huge One Piece fans. There is a pop up cafe event in Shibuya and Shinsaibashi. On the website it says part 1 runs until March 30th and Part 2 starts April 1st. We want to get tickets ideally for April as our stays in Osaka and Tokyo are from March 31-April 5th. However on the website tickets are only available until end of March. Does anyone have an idea of when part 2 tickets will open for advance reservations??