Employee benefits - Narrative (Details) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Apr. 01, 2023 |
|
| Employee Benefits [Abstract] | |||
| Software development costs, employee benefits and consultant fee, capitalised | ¥ 299 | ¥ 291 | ¥ 261 |