I've travelled around Japan a fair bit and I only use primes. As for missing shot because you didn't have zoom, I say it's highly unlikely since there's so much happening there, you will always have a shot of something.
And I always end up coming back with few thousand photos from each trip.
Anyway, my kit is usually 15mm, 21mm, 31mm, 43mm, 77mm primes.
Funny enough in 4 times I've been there I've never used anything longer than 43mm. Also on my last trip in February I've not even used 43mm.
Sticking mostly to 15mm, 21mm and 31mm. You have to remember that streets are narrow and very often you will struggle to get enough distance between yourself and subject, because of that, I always opt for the wider lenses.
I've a number of photos from Japan on my website, so it should show you the focal lengths I've used for each photo (+ other details). Not that I claim to be great photographer etc.
But, here are few photos. First shot with 21mm, 2nd with 15mm and last with 31mm: