The origins of this tree almost sound too good to be true.
It is true that the Japanese are obsessed with sandalwood, and theoretically sandalwood trees should be able grow in Japan, from what I am aware of, sandalwood trees can only grow in the extreme South of Japan, in U.S. Department of Agriculture designated “zone 10”. (That means it’s probably not going to be found growing in areas like Kyoto or Tokyo, although all the modern city development in Tokyo has actually altered the local climate so that the city area falls into zone 10) Sandalwood trees also typically don’t grow very well without a “host” tree planted nearby, of a particular species. So I would think it unusual to find a sandalwood tree in a Japanese garden, though not impossible.
I personally would be a bit skeptical about such claims.
The site that you bought or sourced your oil from does have a picture of a map, with a pinpoint marker that appears to lie in Oita, on Kyushu, Japan’s southernmost major island. However, Oita is more on the north side of the island, rather than the south, and thus falls more into zone 9b.
The site where you got your oil also has a picture that I recognize as Shoganji Zen retreat, located just a little east from Oita. They have some garden grounds. Shoganji is located right near the coast, so that does seem to bode well for the possibility of a sandalwood tree being able to survive there (being located right near a large body of water helps moderate temperatures and prevents it from getting too cold). Oita is a very ancient city and has at least three Buddhist temples nearby, though not as large or impressive as those found in other parts of Japan.
If it means anything to you, I did try doing a search on the Japanese internet, for Shoganji (正願寺), sandalwood (白檀), tree (木) and Oita (大分).
I was hoping to perhaps find a picture of tree they cut down, but no such luck. (I had to specify Oita because apparently there is another more popular temple also named Shoganji in a different part of Japan that dominated the search results)
This Japanese blog says about sandalwood trees: “Although natural growth is considered impossible in Japan due to climatic reasons, it can be seen in several botanical gardens. In Tokyo, it is grown in a greenhouse at the Koishikawa Botanical Garden …”
Mushashino Works
Oil sourced from a 100-year-old tree is extremely rare to find on the commercial market these days. The best quality of oil is said to come from trees older than 70 years.
None of the synthetics really match the real beauty of genuine (Santalum album) sandalwood oil.