Talk:Quests/@comment-3502824-20170405114404/@comment-460323-20170405155128

I think you only need to A-rank for Operation Z. I got the 50% completion when I S-rank 2-4 and 6-1, then it became 80% once I A-rank 6-3.

Which is great, since S-ranking 6-3 and 6-4 ain't exactly the best way to spend your time in Kancolle.