The expressions 後へ引く and 後を引く


What is the logic behind the similar sounding expressions 後へ引く and 後を引く? Are
they idioms? Apple dictionary lists these examples:

**後へ引く**

> もう後へは引けない  
>  'It's too late to turn back now.'  
>  'We're in too deep to back out now.'

**後を引く**

_1 影響が残る_

> 傷の痛みがいつまでも後を引いている  
>  'The pain of the wound [won't go away / still lingers].'
>
> あの事件の後遺症がいまだに後を引いている  
>  'The aftereffects of that incident are still being felt.'

_2 次々に欲しくなる_

> このクラッカーは食べ出すと後を引く  
>  'Once I start eating these crackers, I can't stop.'

The idiomatic meanings don't quite fit the individual words or similar idioms
(eg 潮が引く "the tide goes out" or 事故が後を絶たない "there continue[s] to be [no end to
the] accidents").




This is because 後 has the same roots as 跡. In, the first version 後へ引く, 後
literally means to go backwards, etc. However, the second version does not
mean that, it is closer to 跡. I guess you could think of the meaning as "to
leave a mark". They are both idioms.




This is because 後 has the same roots as 跡. In, the first version 後へ引く, 後
literally means to go backwards, etc. However, the second version does not
mean that, it is closer to 跡. I guess you could think of the meaning as "to
leave a mark". They are both idioms.

