Growing up, I'd always thought that drinking before dusk was considered something of a no-no. When my friend suggested on a recent Sunday that we stop by Koenji Bakushu Kobo to try some jikasei (homemade) beer at 3 p.m., I pushed it to the more respectable hour of 5. By the time we arrived, though, the crowd was spilling out of the bar with plastic cups of beer in hand. Clearly, I was the only person with qualms about afternoon tippling.

As we waited for a table to open up, my companion shot me an I-told-you-so look of reproach. I should have guessed that the bar would be packed: These days, Japan's craft-beer scene is booming. The drink peaked for the first time in the late 1990s, when changes to legislation granted licenses to breweries producing an annual minimum of 60 kiloliters. Since 2005, the volume of craft beer made in Japan has increased steadily, with some breweries seeing year-on-year growth of as much as 40 percent.

In Tokyo alone, there are more than 100 bars and restaurants specializing in domestic and imported craft beer. Bona fide brewpubs, however, remain rare. The most established is T.Y. Harbor Brewery, located on Tennozu Isle, which started production in 1997. Campion, a pub brewing British-style ales in the heart of touristy Asakusa, joined the scene in 2013. Although popular bars DevilCraft and Watering Hole are also expected to turn into brewpubs, neither has begun making beer on site.