Shaun White Snowboarding

This is similar to: Mardi Gras, Octoberfest & Ice Worm achievements so you can do most of this by yourself but you will need to go online to do it and instead of inviting someone to the challenge press Y to do them solo.

You are going to need to play through the single player mode in order to get this achievement because one challenge in each area is locked until you complete Shaun's challenges of collecting coins etc.

I also think that you don't just need to play every challenge but you have to gain at least one medal in each challenge.

These are the challenges you need to complete in Japan

** NOT IN ANY PARTICULAR ORDER **
--------- Can be done solo as described in other solution
1. Boardercross
2. Jibfest
3. Big Air
4. Collect
5. Precision Riding
6. Death Race
7 & 8. Ground Tricking 1 & 2
9. Air Time
10 & 11. Air Tricking 1 & 2
12, 13 & 14. Freestyle 1, 2 & 3
15. Halfpipe (Unlock this via Shaun's challenges, single player)
---------------- Must be Multiplayer -------------------
16. Rat Race
17. King of the Hill

Just play every challenge online in japan. You can do this by yourself by hosting a session and then go to the challenges and press the y button instead of A to invite people. On the 2 multiplayer challenges you have to play with others, though.