～ないことには

[Rei Yahya]

If anyone could offer me insight on to the nai koto ni wa construction, that would be grand. To my understanding it means unless/without.

パーティーに来ないことには僕の作った寿司を食べられない。unle ss you come the party, you can't have the sushi I made.

Is this correct?

 

[Toritoribe]

The main clause of ～ないことには structure is always negative, i.e., the form must be A ないことには B ない, and the nuance is more close to "(can do) B only after/by A". So, you can't say 失敗しないことには負けない instead of 失敗しない限り負けない/失敗しなければ負けない, since "you can lose only after you fail" doesn't make much sense. 失敗しないことには強くなれない "You can become stronger only after you fail." is OK.

 

[Rei Yahya]

So in that case, パーティーへ行かないことには寿司を食べられない is 'you can eat sushi only after coming to the party'?

 

[Toritoribe]

As for the true meaning, yes. Probably there is no problem to translate ないことには as "unless" in most cases, but not all "unless" can be translated to ないことには.