v3.26.1
Deferred taxes and incomes tax expenses (benefits) - Narrative (Details) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2027
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Tax effect of tax losses   ¥ 2,512 ¥ 3,180  
Unused tax losses for which no deferred tax asset recognised   ¥ 5,692    
Tax rate effect of foreign tax rates   30.60% 30.60% 30.60%
Statutory effective tax rate   25.80% 25.80% 30.60%
Current-year losses for which no deferred tax asset is recognized   (26.00%) (6.00%) 0.00%
Rcognized Loss Before Income Taxes, Coincheck Parent and Aplo        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Current-year losses for which no deferred tax asset is recognized   25.00%    
Changes in tax rates or tax laws enacted or announced        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Tax rate effect of foreign tax rates 31.50%      
Next Finance Tech Co, Ltd.        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Unused tax losses for which no deferred tax asset recognised   ¥ 113 ¥ 154  
Aplo SAS        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Unused tax losses for which no deferred tax asset recognised   ¥ 2,180