Five barred gate
A five barred gate is a variation of a 'six of the best' caning. This form of caning is sometimes referred to as gating, and it should not be confused with the boarding school form of grounding also known as gating. Caning was a popular form of corporal punishment in schools in England in the 19th and 20th centuries. A misbehaving schoolboy would be called to the office to receive 'six of the best' from the headmaster. The spanking implement used was a rattan cane.
In a normal 'six of the best', the ideal result of the caning is that, on the spankee's buttocks, there will be six horizontal marks in parallel that are close to each other. However, in a 'five barred gate', the sixth and final stroke of the cane would be delivered at a roughly 30° to 45° down angle, cutting diagonally across the previous five strokes (given horizontally). The marks on the spankee's buttocks would look like a five barred gate, hence its name.
The purpose of the diagonal stroke is to "link" the previous five strokes. Traditionally, the final stroke is meant to be the hardest, and when it is delivered diagonally, it will "open up" the previously inflicted welts and cause more pain.