745 Game laws: rules explained for Rob Burrow tribute match at Leeds Rhinos' Headingley Stadium

The 745 Game, between teams of past players from league and union, combines aspects of both sports. It was devised by Rhinos legend Rob Burrow - who died in June - and ex-Gloucester and Leicester Tigers star Ed Slater. The name comes from the numbers worn by Burrow, Slater and the late Scotland rugby union great Doddie Weir.

All three were diagnosed with motor neurone disease and proceeds will go to supporting fellow sufferers and fighting the terminal illness, which has no known cure. Here’s an explanation of the laws which will be in use on Sunday.

Teams: 13-a-side, six forwards, seven backs. Each team can bring on a specialist only for kicks at goal.

Scoring: five points for a try, two for a penalty, conversion or drop goal.

Tackles: unlimited tackles in your own half, but six tackles once the attacking team passes halfway.

Interchanges: unlimited.

Scrums: uncontested scrums from knock ons and forward passes, taken on the 20m mark in from touch. The attacking team can select on which side of the field scrum is placed.

Lineouts: uncontested five-man lineouts when the ball goes into touch.

One-on-one ball steals: allowed in a tackle before the ball carrier gets to ground; once a knee is to ground the tackle is complete. Play restarts with a play-the-ball.

Markers: two markers at a tackle, offside is five metres from the play the ball.

Referees: one union (Frank Murphy) and one league (Ben Thaler). One will officiate the ruck, the other offside.

Dead in goal: goalline drop out from the defending team, must go at least 10 metres.

Penalties: kicked to touch, re-start with a line out; or take a tap from where penalty is awarded. Advantage for union, but encourages league to attack from penalties.