(Update posted January 2011:) I've updated this recipe for classic tsubu-an or "chunky" style sweet azuki bean paste, originally posted back in June 2006, once again. In March 2010 I added instructions for making it with a pressure cooker - the way I've been making tsubu-an for the last couple of years. Since this was originally posted, I've received a number of comments from people who had trouble with their beans getting soft enough. After some experimentation, I've found that if the beans are fresh you can just add the sugar while cooking without much trouble, but if the beans are a bit old - which is the case more often than not unfortunately - you may run into problems. So, in this latest edit, I've revised the instructions so that people having problems with the (possibly old) beans getting soft enough, will have more success.
A lot of Japanese sweets are based on beans that are cooked with a ton of sugar to a paste-like consistency. Red azuki (adzuki) beans are the most popular kind of beans to use in sweets, and sweet azuki bean paste is called an (餡) or azuki-an （小豆あん).
I've updated this recipe for classic tsubu-an or "chunky" style sweet azuki bean paste, originally posted back in 2006, with instructions for making it with a pressure cooker.