Definition: The subjunctive is a mood because it doesn't deal with factual reality that isn't concrete what someone wants to happen or what might happen but with opinions, wishing, feelings, supposed, doubted, dreams and speculation.
In Japanese language there is not subjuntive form but, some languages will use a form they call "subjunctive" to show that something is contrary to the fact.
There are 5 ways to express "IF" in Japanese Laguage, which are:
|Conditional form in Japan|
|to-----> と||ba-------> ば||nara-----> なら||tara---> たら||tewa--->てわ|
TO: It may also be translated as "when" in English,
BA: It is the most similar to "if" in English.
NARA: It places an assumption of truth on the first clause.
TARA: It shows a condition that the second clause hinges on.