Here are the rules of this interesting betting system.

1. The horse must have had its last start no more than 14 days before its current race.

2. It finished no worse than 4th. and was beaten by no more than 4 lengths.

3. If there is more than 1 qualifier back the horse which raced closest to the current race.

4. If this does not separate the qualifiers, eg. 2 horses both raced 7 days before the current race, then use reliable pre post markets and back the horse that is at shortest odds.