In the same way as the 格助詞（かくじょし） (case-marking particle) と
means ‘and’, sometimes it is translated as ‘if’. In these cases, it is considered to be far stronger than ば
, or たら
(which express hypothetical outcomes). This is because one of the primary uses of と
is highlighting 結果（けっか） ‘a result’. In these cases, と
is actually a 接続助詞（せつぞくじょし）, and shows one of three things.
仮定（かてい）の順接（じゅんせつ） - A result that is assumed to be true, and obvious.
確定（かくてい）の順接（じゅんせつ） - A result that is known to be true.
仮定（かてい）の逆接（ぎゃくせつ） - The opposite of a result that is assumed to be true.
Due to this, the (B) part of a phrase using と
as ‘if’, will always occur when (A) happens, as it is considered to be the result of (A).
If you eat a lot of sweet things, you will gain weight.
If my room is messy, my mother will yell at me.
If my room is quiet, I can't sleep.
If it’s the subway, you will arrive 5 minutes faster.
may not be used in situations where the (B) result ‘might’ happen. It must be definite (or close to definite).
In this particular nuance of と
, despite being translated as ‘if’, the actual meaning is much closer to ‘and’, as と
is expressing that (A) and (B) will always go together.