April 18th is Incense Day.
The oldest record of incense blends in Japan is found in the NIHON SHOKI (Chronicles of Japan), which states that "agarwood drifted to Awaji Island in April of the year 595.
Incense Day was established in 1992 by the National Council of Incense Associations in Japan. The Japanese character for incense, ‘香’ has the letter 18 hidden as 一十八日. Thus April 18th is Incense Day.