いかん
いかん is a variant of いか, “how” (どう). It is old and literary. It is fairly rare.
This particular usage is only used in set phrases, and means something like “how (it is)”
The normal Japanese equivalent is しだい
いかんで
Changes Depending on
Noun + (の) + いかんで
May be いかんだ at sentence end
いかんで is used to express that something changes depending on X.
It usually gives options, or states explicitly that a result will change.
Commonly used with words like 決まる, 変わる, etc.
の may be used before いかんで, but is overwhelmingly dropped.
Sometimes written as 如何で
A variant with the same meaning is いかんによって
Examples
- 賞与は業績いかんだ
Your bonus depends on business performance. - 天気いかんでするかどうかを決める
We will decide based on the weather. - 皆の意見如何でこのサイトは変わる
Depending on people’s opinions, this site will change.
いかんでは
Will Happen Depending on
Noun + (の) + いかんでは
いかんでは is used to express that something will happen depending on something else.
Unlike いかんで, it typically gives a single possible result.
Basically never used with words like 変わる、決まる, etc.
The difference between いかんで and いかんでは is that いかんでは is explicit about a specific result.
(Reference)
いかんで – The Result depends on
いかんでは – You will X depending on
A variant with the same meaning is いかんによっては
Examples
- 頑張りいかんではまだ勝てる
We can still win depending on your effort. - 努力いかんではN1は合格できます
You can pass N1 depending on your hard work. - 天気如何では混雑する。
Gets crowded depending on the weather.
いかんによらず
Not Depending on
Noun + (の) + いかんによらず
如何によらず means “Regardless of” or “Not depending on”.*
Because of this, it is a negative version of いかんでは, since you can’t have options.
いかんによらず uses の to connect to nouns far more commonly than いかんで and いかんでは
Equivalent variants are: 如何に関わらず and 如何を問わず
*よらず here comes from によって (による)
Examples
- 合否の如何によらず, 21日までにメールにて連絡いたします
Regardless of pass or fail, we will contact you by the 21st by e-mail. - 参加の如何に関わらず、月末までにご返答ください
Regardless of whether you will participate, please respond by the end of the month. - 理由の如何によらず、予約は必要です。
Regardless of the reason, an appointment is necessary.