Where does “Мусасино” come from?

Мусасино (Russian) comes from Japanese 武蔵野, from Japanese 野, from Middle Chinese 野.

Ancestry of “Мусасино”, step by step

Step	Language	Word	Meaning
1	Japanese	武蔵野	the Musashino region, the Musashino Plateau: part of the Kantō Plain
2	Japanese	野	an area, field; the hidden part of a structure;...
3	Middle Chinese	野	—