Unknown Chinese Coins Please Help Thanks

HI my grandfather travelled a great deal - in his youth he traveled during the war and later in his years for enjoyment - he never spoke of his time during the war - and it was known in my family to NEVER ask him about that subject - thanks for your info

Yes, it's a catalogue reference. The Krause coin catalogues usually use Krause-Mishler (KM) numbers, but for some series they haven't got around to creating their own numbering system yet and use the numbers from the old Yeoman (Y) catalogue. China is one such series.

KM/Y #10 is the basic type for the Tai Ching Ti Kuo mintmarked 10 cash; subtype d all bear the Chinkiang mintmark and variety 6 is the one with the incused mintmark on a raised disc.

I have double-checked the rarity by looking it up in my copy of the Woodward specialized catalogue for these 10 cash coins; back in 1926 when that chapter of the book was first written, there was only one specimen of that variety (listed as #168 in Woodward) known to exist in private hands; it was rated "unique". The fact that Krause gives no values for this coin means that no genuine examples have been offered for sale in recent decades.