もし details
write + (past) + if
moshi kaita ra
if; supposing — marks the clause ahead as a hypothesis before the condition itself arrives
meaning: if you write
もし迷ったら、この番号に電話してください。
moshi mayotta ra, kono bangou ni denwa shite kudasai.
Call this number if you get lost. neutral
もし試験を受けていたなら、合格していたと思う。
moshi shiken o ukete ita nara, goukaku shite ita to omou.
If I had sat the exam, I think I would have passed. neutral
- た-form
- dictionary form
- past
- negative
- negative + past
- noun
- na-adjective
- ば conditional stem
- た-form
- i-adjective stem
- noun
- na-adjective
- て-form
- noun
- alternant
- alternant
- alternant
Examples
if; supposing — the clause is flagged as hypothetical before the condition is stated
もし迷ったら、この番号に電話してください。
moshimayottara, kono bangou ni denwa shite kudasai.
Call this number if you get lost. neutral
もし僕が君なら、そんな話は断るよ。
moshi boku ga kimi nara, sonna hanashi wa kotowaru yo.
If I were you, I'd turn down an offer like that. casual
もし時間があれば、帰りに寄っていきます。
moshi jikan ga areba, kaeri ni yotte ikimasu.
If I have time, I'll stop by on the way back. neutral
もし嫌なら、無理しなくていいよ。
moshi iya nara, muri shinakute ii yo.
If you don't want to, you don't have to force yourself. casual
もしご都合が悪いようでしたら、遠慮なくお知らせください。
moshi go tsugou ga warui you deshitara, enryo naku o shirase kudasai.
If the timing does not suit you, please let me know without hesitation. formal
もしもの時のために、非常食を用意してある。
moshimo no toki no tame ni, hijoushoku o youi shite aru.
I keep emergency food in case the worst happens. neutral
if it had been — the past inside the conditional says the case never arose, so the main clause looks back at what would have followed
もし試験を受けていたなら、合格していたと思う。
moshi shiken o ukete ita nara, goukaku shite ita to omou.
If I had sat the exam, I think I would have passed. neutral
もしあの日雨が降らなかったなら、二人は会っていなかっただろう。
moshi ano hi ame ga furanakatta nara, futari wa atte inakatta darou.
If it hadn't rained that day, the two of them would never have met. neutral
もし彼が社長でなかったなら、この会社はとっくに潰れてたよ。
moshi kare ga shachou de nakatta nara, kono kaisha wa tokkuni tsubureteta yo.
If he hadn't been the president, this company would have gone under long ago. casual
even if it should — もしも〜ても grants the unlikely case and reports that nothing turns on it
もしも地震が起きても、この建物なら大丈夫でしょう。
moshimo jishin ga okite mo, kono tatemono nara daijoubu deshou.
Even if an earthquake were to strike, this building should be all right. neutral
もしも明日大雨でも、試合は予定どおり行います。
moshimo ashita ooame de mo, shiai wa yotei doori okonaimasu.
Even if it pours tomorrow, we will hold the match as scheduled. neutral
Formation
もし{V-ta}らattaches to た-formもし{P}ならattaches to plain formもし{N}ならattaches to nounもし{NA-stem}ならattaches to na-adjectiveもし{V-ba}attaches to ば conditional stemもし{V-ta}ならattaches to た-formもし{I-stem}かったらattaches to i-adjective stemもし{N}だったらattaches to nounもし{NA-stem}だったらattaches to na-adjectiveもしも{V-te}もattaches to て-formもしも{N}でもattaches to noun
Variant notes
- もしも — the emphatic shape, and the only one in the fixed phrase もしもの時; it pushes the case further into the unreal than plain もし.
- もしものこと — a set phrase for the worst outcome, never named outright — もしものことがあったら、この封筒を開けてください.
- もしもの場合 — the same set phrase in front of a clause of instructions — もしもの場合に備えて、水を用意しております.
Notes
sentence still stands. It marks the conditional; it does not build one.
Related patterns
Similar
万一 rates the case both unlikely and unwelcome and belongs to written warnings; もし rates nothing at all, so it heads happy suppositions (もし宝くじが当たったら) that 万一 cannot.
Lookalikes
The same もし opening splits on what it governs — もしかしたら is a sentence adverb over a guess and closes on かもしれない, while もし needs a conditional ending (たら／なら／ば) and a main clause after it, neither of which もしかしたら takes.
Combines with
A bare たら is ambiguous between "when" and "if" (春になったら reads as a schedule); もし rules the temporal reading out, so a たら naming something certain to arrive refuses it.
なら takes its premise from what the other person just said; もし adds that the speaker is only entertaining the premise, which is why もし本当なら questions the claim where bare 本当なら accepts it.