Am just back from railpassing through a lot of Japan, and lockers are pretty universal. Himeji had all sizes. At Kyoto station, all the large and medium lockers were filled up, but if you go to the Basement 1 level, there is a left luggage room where you can leave pieces until they close at 8pm. They also have a baggage forwarding service there in the station. I didn't check it out throroughly, but it looked like you could even leave bags there by early afternoon and they could be delivered to your hotel/accommodation by later that evening.