1.
just in case, by any chance
Used to express a very unlikely but possible scenario. Literally "one in ten thousand." Often paired with conditional forms (〜たら、〜ば) or the expression の場合は to describe precautionary measures or worst-case scenarios.
万が一に備える。
Prepare for the worst.
万が一のために保険に入った。
I got insurance just in case.
万が一火事が起きたら、この非常口から逃げてください。
In the unlikely event of a fire, please escape through this emergency exit.
万が一 literally means "one in ten thousand" and is used to talk about unlikely but possible events. It is more emphatic than もしも and carries a stronger sense of improbability.
COMMON COLLOCATIONS:
- 万が一に備える (prepare for the worst)
- 万が一のために (just in case)
- 万が一の場合 (in the unlikely event)
- 万が一の事態 (worst-case scenario)
USAGE NOTES:
- Typically used with conditional patterns: 万が一〜たら / 〜ば
- Often appears in formal warnings, safety instructions, and insurance contexts
- Can function as a noun when followed by の: 万が一の時