v3.26.1
Revenue (Details) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Revenue arising from contracts with customers ¥ 477,179 ¥ 383,205 ¥ 223,775
Other sources 3,065 125 274
Total revenue 480,244 383,330 224,049
Contracts With Customers      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Revenue arising from contracts with customers 477,179 383,205 224,049
Contracts With Customers | Commission received      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Revenue arising from contracts with customers 1,345 1,500 729
Contracts With Customers | Other revenue      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Other sources 0 0 274
Sub-total      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Other sources 3,065 125 0
Staking Revenue      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Other sources 2,574 0 0
Investment Management Fee Revenue      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Other sources 139 0
Other Revenue Sources      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Other sources 352 125 0
Retail | Contracts With Customers | Transaction revenue      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Revenue arising from contracts with customers 455,967 381,705 223,046
Institutional | Contracts With Customers | Transaction revenue      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Revenue arising from contracts with customers ¥ 19,867 ¥ 0 ¥ 0