No bind is required to form a ruck, only contact.
LAW 15
FORMING A RUCK
1. A ruck can take place only in the field of play.
2. A ruck is formed when at least one player from each team are in contact, on their feet
and over the ball which is on the ground.
3. Players involved in all stages of the ruck must have their heads and shoulders no lower
than their hips. Sanction: Free-kick.
However, to join an existing ruck, you have to bind onto a teammate or an opponent. This provision was changed a few years ago to prevent the Bakkies Botha style joining a ruck like an
"Exocet Missile".
JOINING A RUCK
5. An arriving player must be on their feet and join from behind their offside line.
6. A player may join alongside but not in front of the hindmost player.
7. A player must bind onto a team-mate or an opposition player. The bind must precede or
be simultaneous with contact with any other part of the body.
8. Players must join the ruck or retire behind their offside line immediately.
9. Players who have previously been part of the ruck may rejoin the ruck, provided they do
so from an onside position.
Sanction: Penalty.
There is a requirement to remain bound but that is only for players alongside the ruck
DURING A RUCK
10. Possession may be won either by rucking or by pushing the opposing team off the ball.
11. Once a ruck has formed, no player may handle the ball unless they were able to get their
hands on the ball before the ruck formed and stay on their feet.
12. Players must endeavour to remain on their feet throughout the ruck.
13. All players in a ruck must be caught in or bound to it and not just alongside it.
14. Players may play the ball with their feet, provided they do so in a safe manner.
15. Players on the ground must attempt to move away from the ball and must not play the
ball in the ruck or as it emerges.
Well they are wrong about Black 20 being offside.
- If he is considered to be in the ruck, he can't be offside,
- If he is
not considered to be in the ruck, then he is behind the hindmost of his team-mates in front of him, so he still can't be offside. .