Boundary 6 .

A boundary 6 is a ball that does not touch the ground until it lands on or outside the boundary. It scores 6 runs, unless there is any pre-match agreement between the umpires and the captains that some other allowance should apply (this may be because of a local convention). For a boundary 6 to be awarded, the ball must have made contact with the striker's bat; it is not possible to score a boundary 6 in No balls, Wides or Byes

It is called a boundary 6 to distinguish it from very rare occasions when the striker might score 6 runs, say, a boundary 4 overthrow following the running of 2 runs, or, on a very large ground, by running all 6 consecutively - with the ball not having crossed the boundary at all but remaining within the field of play.