This video gives a very good overview on the production process of Japanese ink sticks from burning wood and collecting the ashes, adding glue, forming the sticks, drying and adding drawings at the very end.
Ink sticks have been a very practical way of conserving and transporting ink. The ink is obtained by rubbing the ink stick, called "Sumi", upon the surface of a stone vessel called "Suzuri".
Production of ink sticks dates back to the 8th Century. Suzuka City and Nara City are both well known for the production of ink sticks. Most of the production of ink sticks is done by hand during the winter months between October and April in order for the animal glue, used as a binder, to harden well.
The temperature and relative humidity are therefore vital factors in the making of these sticks, which embodies the craftsmanship and heritage of traditional skills.