It very easy to make account on Dragomon Hunter (Japanese game version called Hunter Hero) Japan server.
Dragomon Hunter - Japanese server registration
1. Enter official Hunter Hero site.

2. Select Facebook/Twitter/Google
Dragomon Hunter - Japanese server registration
3. Enter your age, gender and select game.
Hunter hero - Japanese server registration

4. Press big button.
Dragomon Hunter - Japanese server registration
To login in your account follow step 2.
Dragomon Hunter - Japanese server registration
Download Dragomon Hunter, install. After installation finished start Japanese proxy/VPN. (read second part about proxy, both games have similar login system) To enter game you must press Game Start button.

If you have problems with browser i suggest to use Internet Explorer. Most Korean/Japanese games that force users to login from browser work fine only in IE.

After login for first time you need to input your secondary password. Put 111111 111111.