Which imported dogs were likely included in the crossbreeding to create the Japanese Spitz?

Answer

The white German Spitz, the Keeshond, and other miscellaneous white Spitz varieties

Breeders crossbred various imported Spitz-type dogs, specifically mentioning the white German Spitz, the Keeshond (klein wolfsspitz), and other white Spitz varieties from locations like China, Canada, and the US.

Which imported dogs were likely included in the crossbreeding to create the Japanese Spitz?
rarityDogbreedJapanese Spitz