The following list of numbers represents the date of manufacture followed by the piano serial numbers. The letters ‘sn’ mean serial number.
Piano Manufacturer: Yamaha
1958 sn-89000 1968 sn-689000 1978 sn-2583000 1988 sn-4492000
1959 sn-1030001969 sn-809000 1979 sn-2812000 1989 sn-4650000
1960 sn-1220001970 sn-978000 1980 sn-3000100 1990 sn-4808000
1961 sn-1490001971 sn-1169000 1981 sn-3261000 1991 sn-4966000
1962 sn-1880001972 sn-1317000 1982 sn-3464000 1992 sn-5124000
1963 sn-2370001973 sn-1510000 1983 sn-3646000 1993 sn-5282000
1964 sn-2980001974 sn-1743000 1984 sn-3832000 1994 sn-5440000
1965 sn-3680001975 sn-1943000 1985 sn-3988000 1995 sn-5598000
1966 sn-4890001976 sn-2144000 1986 sn-4157000 1996 sn-5756000
1967 sn-5700001977 sn-2383000 1987 sn-4335000
Yamaha America, South Haven, Michigan (Letter U.)
1974 sn-101000 1978 sn-117000 1982 sn-150000 1986 sn-186000
1975 sn-102000 1979 sn-124000 1983 sn-160000 1987 sn-198000
1976 sn-107000 1980 sn-132000 1984 sn-167000 1988 sn-210000
1977 sn-110000 1981 sn-141000 1985 sn-174000 1980 sn-220000
Yamaha America, Thomaston, Ga. (Letter T.)
1983 sn-500000 1985 sn-503000 1987 sn-100000 1989 sn-110000
1984 sn-501500 1986 sn-504050 1988 sn-102200 1990 sn-119000
Piano Manufacturer: Young Chang
Upright Pianos
1978 sn-7800001981 sn-810000 1984 sn-009400 1987 sn-0261000
1979 sn-7900001982 sn-001000 1985 sn-014700 1988 sn-1300000
1980 sn-8000001983 sn-004000 1986 sn-019950 1989 sn-1433342
Grand Pianos
1978 sn-780000 1981 sn-810000 1984 sn-011000 1987 sn-026100
1979 sn-790000 1982 sn-004700 1985 sn-016000 1988 sn-032000
1980 sn-800000 1983 sn-007300 1986 sn-019600 1989 sn-045739
Piano Manufacturer: Zimmermann
1960 sn-195001 1965 sn-215001 1970 sn-246001 1980 sn-400001