This is a well known game related to Gomoku.
It has an important extra rule that allows capture of pieces, when
two pieces are trapped between enemy pieces. This rule makes the
game much more interesting than Gomoku, giving the game stages of
positional play that become broken up by tactical fireworks. This
gives the game much more depth. It is played in serious competitions
in the US and Germany. Gobang will burn up your free time as you
work out how to win it!