Incense is a fragrant stick or powder, lit and let burn or rather glow to give your room a special atmosphere. It is often used at temples, and has since ancient times played an important role in Buddhism, for example at Mt Koya in Japan, in the Kii Mountain Range in Wakayama prefecture south of Osaka and Kyoto.
Here I found a most wonderful shop, called Koyasan Daisido, selling many kinds of incense for different types of ceremonies. They also display fragrant wood from various countries in Asia, including Vietnam, which are increasingly rare and difficult to find.
I was surprised to discover actual twigs or cuts from branches of 伽羅 kyara or agarwood:
The odour of agarwood is complex and pleasing, with few or no similar natural analogues. As a result, agarwood and its essential oil gained great cultural and religious significance in ancient civilizations around the world, being mentioned throughout one of the world's oldest oral texts - the Sanskrit Vedas from India.
You can also buy 白檀 byakudan or pure sandalwood from India, a fragrance so very common in most types of incense. What you will not find here in this very traditional shop, though, is the New Age style incense or aroma therapy style oils increasingly common (but frankly the chemical ingredients can be quite suspect).
This sandalwood incense, for example, is from Mysore, India, a high quality source. Australia produces sandalwood, and Hawaii was also once a source (ʻiliahi), that was unfortunately depleted around 1825.
Yamada Matsuya is a famous incense shop in Kyoto. This Youtube video shows how they make incense, the Japanese way (no sound):
Another popular company is Nippon Kodo, that does a lot of TV commercials. Here is one for their obon incense, that they call "Natural." They are introducing incense at a booth from July 1st to August 31st at the Japanese Industry Pavilion of the 2010 Shanghai Expo:
We have been noted as the best seller of all booth exhibitors and it has become big news: as big crowds of visitors are gathering in front of our booth every day. Ka-fuh/Scents in the wind and Kayuragi seem to be especially popular. Please take a chance to stop by our booth if you plan to visit the Shanghai Expo this summer.
Here is another classic CM from 1990, to get people to burn incense every day （毎日香 Mainichi Kou):
The shop at Mt Koya notes that certain products that they sell are subject to restrictions under the special convention called CITES. This is an international treaty that "works by subjecting international trade in specimens of listed species to certain controls." These require that all import, export, re-export and introduction of species covered by the convention has to be authorized through a permitting system. Roughly 5,000 species of animals and 28,000 species of plants are protected by CITES.
As we all learn more about the importance of biological diversity, we also realize that even a simple joy like burning a stick of incense on a day like this, August 6, or next week during Obon, can have large, global implications.