Here a very fine example showing a technic which is called "switching the point". This technic does bring an open point with a blot closer to the builders, which are waiting in the outfields. "Switching the point" is mostly used in a <blitz> - try to close the opponent out in the early game to possibly winning a gammon.

Black cannot close his 1pt with one of his builders from 10pt oer 13pt. The right play is 6-> 5* -> 1, which brings a second white checker on the bar and "switches" the blot from 1pt to 5pt. This gives Black the possibillity, to close 5pt with any 5 oder 8 at next roll if his checker there is not hit. Further, there is the chance to his a third black checker on 14 Pt.

Cube action:

If Black does not hit the white checker on 5pt, the position is too good for a double because of the gammon-chance. Black will pass, if doubled.

To play the "4" is easy - simply 10 -> 6, closing 6pt.  Do not play the "1" without thinking first. "4 -> 23 is wrong, because this would give Black the chance to play in with 5+5 and hit in the process on 10 pt.

The chance for 5+5 ist aprox. 3 per cent only, but little chances add.