Brewing beer at home in Japan is against the law if the beer contains 1% or more alcohol. For those that can read Japanese, here is the citing from the National Tax Agency website. Otherwise, let this be a warning.
But, it's not like I can't write my "memoirs" of the days when I used to brew beer...so, without further ado, here we go.
First, you need to ask yourself, why do you want to brew your own beer? Because it sounds interesting? Do you think it might be cheaper? Do you want a specific character in your beer, such as a fruity bouquet, higher alcohol content, strong bitterness, sweetness, color, etc.?
Here's some things you need to be aware of before you take the plunge. First, it may sound interesting, and it can be tremendous fun if you don't mind maintaining a sanitary kitchen. This is much easier said than done, although not terribly difficult if you understand what sanitation means. Secondly, in most cases, it actually is cheaper to BYO (brew your own) than to buy commercially available beer because you're not paying taxes. In Japan, a 633-ml bottle of beer costs about 45% in taxes. Finally, it is against the law to produce beer with an alcohol content of 1% or more. It doesn't matter whether it's for personal consumption. It's simply illegal.
If you can accept those terms, then you'll find this series of articles about homebrewing (a work in progress) to be very informative. I'll be describing the process, and what each ingredient can and can't do for your beer. I'll also go into advanced techniques such as mashing, dry hopping, yeast culturing, sanitation techniques, and how to rig your refrigerator so that you can ferment lagers.
If you can't accept all of those terms, don't worry. Craft beers can be sampled or bought almost anywhere in Japan these days. The same can be said for the US. You just have to know what kind of beer you like, and where to find it. To that end, I'll be posting some links to places that I've been to in Japan. For now, this is just a preface to my version of Charlie Papazian's "Joy of Homebrewing" (Amazon link: http://www.amazon.com/Complete-Joy-Homebrewing-Third-null/dp/0060531053).