v3.25.2
Fair value measurement - Private warrant liabilities (Details) - Level 3
¥ in Millions
4 Months Ended
Mar. 31, 2025
JPY (¥)
Disclosure of fair value measurement of liabilities [line items]  
Initial recognition, December 10, 2024 ¥ 56
Change in fair value (45)
Foreign exchange impact 1
As of March 31,2025 ¥ 12