It was invented in 1983 by Hideo Fujiwara and Takeshi Shimono at the Department of Electronic Engineering, Osaka University, Japan.
The FAN algorithm succeeded in reducing the number of backtracks by adopting new heuristics such as unique sensitization and multiple back tracing.
In order to reduce the number of backtracks, it is important to find the nonexistence of the solution as soon as possible.
When we find that there exists no solution we should backtrack immediately to avoid the subsequent unnecessary search.
These heuristics can lead to the early detection of inconsistency and decrease the number of backtracks.