The key to selecting the best azuki beans for making delicious Japanese confections is the balance of the following five factors.
1. Astringency after boiling
2. Softness of the skin after boiling
3. Sweet aroma like marron flavor after boiling
4. Smooth texture after boiling
5. Roundness, size, color and gloss of azuki before boiling
These five factors save confectioners about two to three hours of work compared to azuki beans from other regions, and also help create a sense of high quality in terms of taste.