Runnet.jp is a database and registration site covering all of Japan. You can register for events of all lengths - 5k, 10k, half marathon, full marathon, ultra marathon and more.
It's all in Japanese, so here's a guide to help you through using it.
- Near the bottom of the Runnet page you will find this icon:
This is the link to sign up. It's free.
- Scroll down to the bottom of the signup page and click the red button.
- On the next page, check the option marked 利用規約に同意する
- Next, enter your email address in both of the boxes and click the red button.
- Click the next red button and you will be emailed an activation link.
- Go to your inbox and click it.
- You have 30 minutes to do this. After that, you will have to re-apply.
The best way I can think of (if you don't understand enough Japanese) is to have a version of the page open in Google Translate, and one in the original Japanese (the translated version often doesn't work properly when you try to submit it). Cross referrence to fill out the form.
- Password needs to contain numbers
- The furigana (ふりがな) version of your name (in the boxes under where you first write your name) has to be written in Katakana.
Searching for races
It helps if you know the kanji for the prefecture in which you're searching, better still the city. If not, you'll have to look it up.
Click this and you'll find a list of entry prices. Click エントリー again here and you will need to enter some details (varies per race/type but usually past/expected times, t-shirt size etc).
After sucessfully completing that, you'll be sent to the payment page. You can pay by card or convenience store. The site charges between 100 and 200 yen commission per entry.
Click next, then the submit button at the foot of the confirmation page. You've done it all right when you see this message:
In short, it's a challenge to get through, but it's worth it.