The Exceptional Abacus of Bugidai Addisuson is a 705 years old piece made by Bugidai Addisuson, a merchant living in Ulaanbaatar.
Considering its age and the quality of the work, people consider it of considerable value.
It is engraved with asian patterns and some symbols pertaining to Hinduism.
This piece doesn't exist, but as a legend. It is said that in the year 2079, James Addisuson, the owner, made use of it in New York to empower the Addisuson family. Now it is lost, or broken, we will never know.