The Australian Open was not held in 1986 because the tournament moved from its December slot to January 1987.
From 1982 through 1985, the championship was played in mid-December. Organisers then shifted the event forward to establish a January schedule, but the change left no tournament in the 1986 calendar year. The next edition began in January 1987.
The missing year is easy to confuse with 1977, when the opposite scheduling problem produced two Australian Opens: one in January and another in December. In 1986, there was simply no edition at all. The tournament's dates had fluctuated before, partly because of Australia's summer conditions and the event's traditional holiday timing.
The January schedule became the lasting pattern. The 1987 tournament was still played at Kooyong on grass, while the move to the new Flinders Park complex in Melbourne followed in 1988. That venue was later renamed Melbourne Park, where the Australian Open remains based.