Unsure what the rule-book says and totally unsure how the refs rule on it. If the defenders stop the progress of an attacker, I would call that a 'held tackle', but as they stop to allow the play-the-ball, the attacker invariably slips one away and they call it an off-load. If they don't let him go, they penalise for hanging on too long. Even when they fell the attacker and hang on to the legs either too long or not long enough - same thing happens; they let him go to play the ball and slimy bugger scampers off again. Even the players are mystified by the refs non-called 'Held', as in Foz las night being penalised. The refs have got to call 'Held' each tackle otherwise it's a farce!