Incense has been a cultural phenomena and has served many purposes in various cultures through-out the world. China and Japan in particular have led particularly rich histories involving incense and inevitably, at one point in time, it was used to measure time as well. It began with rudimentary knotted match cords, and later progressed to incense sticks, which are referred to as senko in Japanese, incense coils and eventually more elaborate powdered incense trails.
In ancient China and Japan, the prevalence of incense time-keepers began being reported in the 17th century by western missionaries and travelers. One of the earliest reports began within the diary of Mattero Ricci (1552-1610), who was the founder of the Jesuit mission in China. The Jesuits were a catholic religious congregation, originating in Spain, who grew to fame through missionary and evangelization efforts. An entry written within the diary in 1601, while Mattero was in Beijing, he reported that at that point in history, there were only several methods to measure time, and they were based around different elements, such as water or fire.
According to the Tokei Hattatsu-Shi by Hyoe Takabayashi, the methods of using incense (koh) as a time-keeping in Japan paralleled those which had developed in China. Many Japanese traditions, in general, were borrowed from China, and many presume time-keeping methods to be no different.
The simple knotted match cord is one of the earlier methods which fall under the incense time-keeping umbrella. A specific length of knotted cord is formed from punk, which is made from either decayed wood or a spongy substance made from fungi. Spaces between each knot indicated a specific length of time, and as the rope burned, time was recorded. Punk is similar to incense in the regard that they both burn at a slow space and began the origins of time-keeping traditions. Occasionally military personnel would place lit knotted rope between their toes as sort of a primitive alarm clock.
At this time, incense sticks, also known as joss sticks, were most commonly made from sandalwood and elm root, which were ground and worked into a paste with water. The mixture was then hardened onto wood or bamboo sticks.
After the incense sticks were made, the time required for the formulation was recorded, observed, and then used as a standard time measurement. Later on they began marking incense sticks in intervals to allow for a more consistent measurement, as well as multiple uses.
Incense Coils & Primitive Alarm Clocks
Incense coils were another popular form of incense throughout Asia, and were used to tell time as well. Incense paste was forced through a draw-plate to produce a coil, but other then that, the formulations themselves were quite similar. Incense coils were rather unique due to being laid on a hook and suspended in the air while burning. Although notably popular among civilians and royalty, incense coils were also used as offerings in Buddhist temples.
Another use for incense in regards to time was a primitive form of alarm clock. Incense sticks were placed into a special vessel, usually cast in bronze and measuring two feet in length. These alarm clocks were often shaped like a dragon and once the incense was placed within and burned, a thin string supporting weights was stretched across the vessel. When the incense sticks burned to a designated point, the weights would clunk onto the brass vessel and create a ringing sound, meant to wake the user from his or her slumber.