The All Japan Dojo Elementary Student's Tournament is a truly massive event, with thousands of kids, squeezed into the Nihon Budokan every year.
As someone who would teach Kendo to elementary kids in Japan, this tournament was always something we would aim for, and it was basically the biggest event in the calendar for kids of this age.
This year's final saw the Fukuoka powerhouse Josuikan take on Tokyo's Akishima Chuo for an energetic and exciting match. This tournament is for all kids that are primary/elementary, and it is mixed, so boys and girls fight together. because of this, there are often vast differences between heights and sizes, but that often makes the matches even more exciting. Check out the Taisho match of this video (starting around 9:28) for a great example of what I mean :
Video from: 剣道総合サイト LET'S KENDO