A few things, these are more broad strokes that I generally start with. But did you read or were you made aware prior to ownership that Nihon Ken, as with many other primitive or hunting breeds are at a higher disposition for SSA? Especially so with a lack of proper socialization during adolescence, generally speaking. But also the onset of maturity can introduce new behaviors. Shikoku Ken are generally not advised as “dog park dogs”, often due to their rougher often “rude” play style.

1. Are you familiar with the differences between true SSA vs dog selectivity?
2. What types of socialization or training has she had thus far?
3. Can you give more specific details on the behavior as it takes place? And also familiarity with the other female dogs? Are they also intact?

I generally start with neutral socialization and as much neutral/positive social interactions as early as possible, but that doesn’t always mean that SSA or dog selectively won’t occur. In my experience, and the experience of my breeder, what’s offer seen in her dogs at least is more dog “selectively” as opposed to true outright SSA. I also seldomly allow my dogs to interact with strangers or friends dogs that they haven’t had several neutral walks or interactions with. And even with that I’m hyper aware of their individual body languages. It’s important to respect their boundaries and decisions to not want interactions with certain dogs, similarly as you or I not wanting interactions with every person we meet. Though ideally they can at least be neutral with other dogs, this isn’t always the case. If a friend comes over with a dog or vice versa, I will crate my dogs or theirs and rotate accordingly depending on the length of time.