The system of classifying kohboku, which constitutes the basics of appreciating incense, is called Rikkoku-Gomi. This refers to the six ancient East Asian countries where kohboku woods originate, and the five elements used to describe their flavors. The names of countries (Kyara, Rakoku, Manaka, Manaban, Sumotara, Sasora) all represent a qualitative classification of kohboku wood, and five terms (hot, sweet, sour, bitter, salty) are used to describe the different essences.
A piece of kohboku wood can generate more than one fragrance when burned. Kohboku pieces often have a mixture of multiple fragrances, generating an indescribable blend, depending on the proportion and strength of each essence contained in a piece of wood.