This does take place before What Is Love, which I suppose is a little odd, but I believe is ultimately for the best for a few reasons. One of those reasons is I like the reveal of Nanase's hair, and another is that What Is Love wouldn't really fit with the rest of the summer storylines. It would more just be there to be in the right spot chronologically,

A fair question one could ask prior to this point is "why has Nanase been allowed to take martial arts?" Well, Nanase's mother might want Nanase to one day be a stay at home mom, but darn it, that's not a position she takes likely. Moms have to be intelligent, knowledgeable, and capable of utterly destroying anything that dares to threaten their children.

Granted, I think most moms can do that by the power of motherly instinct alone, but add martial arts to that and mama's ready to bring on the pain.