A boat sails the course when
(a) she starts
(b) a string representing her track until she finishes, when drawn taut,
(1) passes each mark of the course for the race on the required side and in the correct order (including the starting marks),
(2) touches each mark designated in the sailing instructions to be rounding mark, and
(3) passes between the marks of a gate from the direction of the course from the previous mark; and then
(c) she finishes.
A mark that does not begin, bound or end the leg the boat is sailing does not have a required side.