PLAYER 1 controls the ODD rows (rows 1, 3, and 5). That means that when the board is all filled except for one remaing column, player 1 will always be able to put their piece in an odd row postion in that last remaining column. So player 1 will always win by thinking long-term and setting a trap (where the last piece needed to win is in an odd row).

PLAYER 2 controls the EVEN rows (rows 2, 4, and 6). That means that when the board is all filled except for one remaing column, player 2 will always be able to put their piece in an even row postion in that last remaining column. So player 2 may win by thinking long-term and setting a trap (where the last piece needed to win is in an even row).