As time goes by, ink sticks change from moment to moment. It is caused by the secular change in the bone glue and the related spontaneous agglomeration of the soot, creating richness in the tone of ink black. This is why it is said that the old ink sticks are good. Kogaboku is a series of the ink sticks produced more than 30 years ago.
This series can be called the root of hyakusenboku. Usually, as for Japanese ink sticks, kozumi (deep black ink) is beautiful and as for Chinese ink sticks, usuzumi (light black ink) is beautiful whereas Daiwagaboku has both advantages of Japanese ink sticks and Chinese ink sticks. So it is possible to express a wide range of black tones with this Daiwagaboku ink stick. The older the ink stick, the richer taste it has.
It is a painting ink stick created by kneading inorganic pigments and animal glue. It has a deep color tone unique to inorganic pigments.