This set of two Snoopy dolls is for a Hinamatsuri (Girls' Day or Doll Festival) celebration. (a) refers to the Snoopy doll in blue, and (b) refers to the slightly larger Snoopy dog in red (possibly meant to be Snoopy's sister Belle). Belle is wearing a red, white, and yellow kimono wtih floral designs and a gold crown held on by a red cord. Snoopy is wearing a blue and white kimono with a geometric floral pattern and a gold crown held on by a blue cord. Both dolls are sitting on red cushions with green tassels at each corner.
Snoopy is a character from the comic strip Peanuts (1950-2000) by Charles M. Schulz. He is a white dog with black spots who belongs to Charlie Brown.
Hinamatsuri, the Doll Festival or Girls' Day, is held annually on March 3 to celebrate the happiness and health of young girls. The holiday originated during the Edo period (1600-1868) to ward off evil spirits, and at some Hinamatsuri festivals today, people release paper dolls into the rivers to carry away sickness and bad fortune.