Guide "to" VS. "on" VS. "for", which is correct?

In general, guides are "to" whatever they describe, whether this is an action or a thing: 

• A guide to living in Japan
• A guide to the City of Tokyo
• A guide to 21st-century Performance art​

However, the form that the guide is published in, whether it is a book, a web page, an article, or anything else, would usually use "on": 

• An essay on the City of Kanagawa
• A book on building your own nuclear weapons
• A web page on 21st-century Performance artists

"For" is used to say who the guide is aimed at, not what it describes: 

• A guide for juveniles
• A guide for car owners​ 
• A guide for Single Moms

I would be a little surprised to see something like "A guide for building your own space rocket," where "for" indicates purpose, and "A guide for seventeenth-century Flemish art" would be wrong.

Yes, the preposition after "guide" must be followed by a specific purpose if you want to use "for," so I still recommend you to use "to" because it applies to most situations.

So I changed my website Name, "Guidebook for Living in Japan," to "Guide to Living in Japan."