v3.25.2
Deferred taxes and incomes tax expenses (benefits) - Total deferred tax assets and liabilities (Details) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Apr. 01, 2023
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets ¥ 885 ¥ 858  
Deferred tax liabilities 499 505  
Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 885 858 ¥ 890
Recognized through profit or loss (22) (32)  
Addition (business combination) 49    
Deferred tax liabilities:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liabilities 499 505 151
Recognized through profit or loss (6) 354  
Addition (business combination) 0    
Lease liabilities | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 425 522 107
Recognized through profit or loss (97) 415  
Addition (business combination) 0    
Tax losses carried forward | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 49 26 493
Recognized through profit or loss (26) (467)  
Addition (business combination) 49    
Accrued enterprise tax | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 49 36 0
Recognized through profit or loss 13 36  
Addition (business combination) 0    
Accrued bonuses | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 98 71 0
Recognized through profit or loss 27 71  
Addition (business combination) 0    
Accrued expenses | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 76 98 58
Recognized through profit or loss (22) 40  
Addition (business combination) 0    
Accrued paid leaves | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 16 16 17
Recognized through profit or loss 0 (1)  
Addition (business combination) 0    
Reversal for valuation gain of crypto assets held (non-current assets) | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets   0 12
Recognized through profit or loss   (12)  
Leasehold improvements | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 36 19 45
Recognized through profit or loss 17 (26)  
Addition (business combination) 0    
Impairment loss of crypto assets held (non-current assets) | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets   0 21
Recognized through profit or loss   (21)  
Change in fair value of crypto assets held (non-current assets) | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets   0 23
Recognized through profit or loss   (23)  
Write-down for crypto assets held (current assets) | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets   0 27
Recognized through profit or loss   (27)  
Asset retirement obligations | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 107 37 69
Recognized through profit or loss 70 (32)  
Addition (business combination) 0    
Other | Deferred tax assets:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax assets 29 33 18
Recognized through profit or loss (4) 15  
Addition (business combination) 0    
Lease assets | Deferred tax liabilities:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liabilities 395 499 107
Recognized through profit or loss (104) 392  
Addition (business combination) 0    
Asset retirement obligation | Deferred tax liabilities:      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liabilities 104 6 ¥ 44
Recognized through profit or loss 98 ¥ (38)  
Addition (business combination) ¥ 0