To provide a connection system or binding capable of easily switching a ski mode with a snowboard mode.

A split board has a first ski board mountable on a second ski board releasably to be operable in a snowboard mode and a ski mode. A corresponding toe bracket is attached to the first and second ski boards. A pair of front slider blocks and a pair of rear slider blocks are attached to the first and second ski boards. Left and right bindings include a front hook part configured so as to be engaged with the corresponding toe brackets releasably. The bindings are configured so as to be engaged with front and rear slider blocks slidably in the snowboard mode. A tension loop is pivotable from a lock position, and prevention parts of the tension loop extend through openings of the bindings to be engaged with the slider blocks at the lock position. Heel stoppers extend downward from the bindings to limit forward sliding of the bindings.