Japanese characters in running script - Gen Yu Tsu Ho (one-dot Tsu) / Blank. 23.5mm, 3.08 grams. Mint in Kyushu, issued ca.1580-1620. Hartill (Japan) #3.106 var (with a one-dot Tsu).
These coins are associated with Kyushu, the most south-western part of the islands of Japan. These are also known as Kajiki-sen, after a village of Kajiki in Osumi province.
From a beautiful collection of Japanese coins we recently purchased.