Note 6 — Chapter VIII · WOO-CHANG, OR UDYANA. MONASTERIES, AND THEIR WAYS. TRACES OF BUDDHA.
James Legge translation
(6) Soo-ho-to has not been clearly identified. Beal says that later Buddhist writers include it in Udyâna. It must have been between the Indus and the Swat. I suppose it was what we now call Swastene.