On a full-size snooker table, the baulk line is 29 inches from the nearest cushion.
The line runs across the table near one end and forms the straight edge of the D. The D is the semicircular area behind the baulk line from which the cue ball is played at the start of a frame and after certain fouls.
The baulk area contains the yellow, green and brown spots. Looking from the baulk end, the yellow and green spots sit to either side of the D, while the brown is positioned centrally on the baulk line. The measurement helps standardise the tactical opening layout on tournament tables.
This distance is often confused with the table’s overall dimensions or with pool-table markings. It refers specifically to the playing surface of a full-size snooker table, not the outer wooden frame.