v3.25.2
Supplemental cash flow information (Details) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Apr. 01, 2023
Changes in liabilities arising from financing activities [abstract]      
Liabilities arising from financing activities at beginning of period ¥ 1,661 ¥ 350 ¥ 439
Proceeds from short-term loans 1,800 1,200 1,800
Repayments of short-term loans (1,800) (1,200) (2,000)
Repayments of long-term loans 0 0 0
Repayments of lease obligations (463) (327) (255)
Proceeds from loans from related party 8,508 0 3,000
Repayments of loans from related party (7,887) 0 (3,000)
Total changes from financing cash flows 158 (327) (455)
Modification of lease term 79 (81) 253
New lease contracts   1,719 113
Increase by business combination 130    
Interest expenses 31 5 3
Interest expenses paid (31) (5) (3)
Total liability-related other changes 209 1,638 366
Liabilities arising from financing activities at end of period 2,028 1,661 350
Right-of-use assets obtained in exchange for lease liabilities 366 1,638 79
Warrant and other liabilities assumed 2,347    
Loans      
Changes in liabilities arising from financing activities [abstract]      
Liabilities arising from financing activities at beginning of period 0 0 200
Proceeds from short-term loans 1,800 1,200 1,800
Repayments of short-term loans (1,800) (1,200) (2,000)
Repayments of long-term loans     0
Repayments of lease obligations 0 0 0
Proceeds from loans from related party 8,508   3,000
Repayments of loans from related party (7,759)   (3,000)
Total changes from financing cash flows 749 0 (200)
Modification of lease term 0 0 0
New lease contracts   0 0
Increase by business combination 2    
Interest expenses 21 0 1
Interest expenses paid (21) 0 (1)
Total liability-related other changes 2 0 0
Liabilities arising from financing activities at end of period 751 0 0
Promissory note- related party      
Changes in liabilities arising from financing activities [abstract]      
Liabilities arising from financing activities at beginning of period 0 0 0
Proceeds from short-term loans 0 0 0
Repayments of short-term loans 0 0 0
Repayments of long-term loans     0
Repayments of lease obligations 0 0 0
Proceeds from loans from related party 0   0
Repayments of loans from related party (128)   0
Total changes from financing cash flows (128) 0 0
Modification of lease term 0 0 0
New lease contracts   0 0
Increase by business combination 128    
Interest expenses 0 0 0
Interest expenses paid 0 0 0
Total liability-related other changes 128 0 0
Liabilities arising from financing activities at end of period 0 0 0
Lease liabilities      
Changes in liabilities arising from financing activities [abstract]      
Liabilities arising from financing activities at beginning of period 1,661 350 239
Proceeds from short-term loans 0 0 0
Repayments of short-term loans 0 0 0
Repayments of long-term loans     0
Repayments of lease obligations (463) (327) (255)
Proceeds from loans from related party 0   0
Repayments of loans from related party 0   0
Total changes from financing cash flows (463) (327) (255)
Modification of lease term 79 (81) 253
New lease contracts   1,719 113
Increase by business combination 0    
Interest expenses 10 5 2
Interest expenses paid (10) (5) (2)
Total liability-related other changes 79 1,638 366
Liabilities arising from financing activities at end of period ¥ 1,277 ¥ 1,661 ¥ 350