From Yamaha Wiki
The term Yamaha Artist refers to musical instrumentalists (or artists) who choose, officially, to play any of a large group of Yamaha (manufacturer) musical instruments.
The program of artists endorsing Yamaha is managed by Yamaha Corporate Artist Affairs, located in Franklin, Tennessee. There is also an office in New York City which exclusively handles Yamaha Artists in the European classical music field, as relates to Yamaha Pianos and Yamaha Band and Orchestra instruments - namely those in the brass and woodwind families. Other offices relating to Yamaha Guitars and Yamaha Drums are located in Buena Park, California. The office in New York is known as Yamaha Artist Services, Inc. and was founded in 1987 and serves the world of Yamaha classical piano artists.
Additionally, there exists a growing web of Yamaha Artist Services offices in such cities as Paris, Seoul, London, Tokyo, and Moscow.