most of bisguier's play after the mid-1960s was limited to u.s. events. he won national opens in 1970 (jointly), 1974, and 1978. he won the lone pine tournament in 1973, tied for second place behind reigning world champion boris spassky in the international tournament in san juan, puerto rico in 1969, and took first place in the first-ever grand prix in 1980. he took first place in the u.s. senior open in 1989, thus winning a u.s. championship at every age level of chess. he won the senior open again in 1997 and 1998.