Sideways glance ... Bulldogs front-rower James Graham stands to the left of marker Greg Eastwood against the Raiders.
THE Bulldogs have one of the best defensive records in the NRL, preventing the opposition scoring tries from within 20 metres of their own line.
And now their grand final opponents tomorrow, the Storm, know why.
A careful scrutiny of video footage of Canterbury's defence near their own posts demonstrates that their markers are rarely onside, often standing laterally, rather than immediately and directly in front of the man playing the ball.
It's a tactic that shuts down clever dummy halves, such as Melbourne captain Cameron Smith, the best forward in the game.
Newcastle coach Wayne Bennett rang his former Broncos assistant Kevin Walters, who is now deputy to Storm boss Craig Bellamy, and alerted him to the tactic.
However, Bellamy had already noted the ploy and warned Smith.
Stills taken from recent matches clearly show this is a rehearsed tactic, rather than an ad hoc one.
In a game against the Raiders, who were leading 12-6 on a third tackle, the Bulldogs' James Graham as second marker, stands to the left of and beside the first marker, with Aiden Tolman positioned behind the ruck.
Fourteen seconds and one tackle later, it's backup hooker Joel Romelo as first marker who is standing to the left of the man playing the ball and moving behind him, while Graham, again as second marker, has split to cover the right-hand side of the ruck. It effectively shuts down the Canberra dummy half, restricting his options.
Romelo's position basically commits the Raiders to pass to their left, meaning a carefully rehearsed offside double marker defence can prevent an attacking team from using one half of the field.
In a match against Wests Tigers, with the Bulldogs again defending their own line, hooker and captain Michael Ennis is also offside.
Against Manly, with the Bulldogs leading 12-10 on the second tackle, Ennis again has gambled he won't be penalised as second marker and is standing to the right of the first marker, Graham.
Canterbury's worst offenders are Ennis, Tolman and Graham.
It's not as if this trio or their teammates don't have time to release themselves from the tackled player and occupy marker positions according to the rules.
A study of video footage in real time shows Canterbury players have ample opportunity to regain their feet and stand one behind the other, rather than side by side.
Usually, defensive players are very conscious of conceding penalties close to their own posts, risking an easy two-point kick, or another set of six that could lead to a try.
However, Bulldogs coach Des Hasler has obviously exploited the fact referees tend to focus on the defenders on the try line to determine if any are offside, rather than at the ruck. Or, the referees are caught up in the intensity of the action so close to the line.
The tactic becomes very valuable during the semi-finals when referees tend to blow fewer penalties.
It's difficult to anticipate how Bellamy can counter it if the referees don't warn the Bulldogs tomorrow.
One option would be for dummy half Smith to deliberately step in the direction of the offside Bulldog marker, highlighting his illegal position and win a penalty.
Smith was quoted this week saying his team lost to the Bulldogs in round 20 (they had won 12-6 in round seven), basically, because they could not score, despite multiple sets on the Canterbury line.
Sportsdata statistics show that Canterbury has one of the NRL's best records when it comes to conceding tries within 10 metres of their line. While Manly and Brisbane have conceded fewer tries close to their posts, they haven't had the weight of attacking sets thrown at them the Bulldogs have endured all season.
A defensive statistic devised by Sportsdata, combining metres and tackle numbers yielded as a result of penalties, shows the Bulldogs with a score of 5608 metres, compared with the Storm's 4161, the Sea Eagles' 4382 and the Rabbitohs' 3925. It means the Bulldogs have defended more metres and tackles against them from penalties than any other top four team, yet still can protect their own line.
The wily Hasler has alerted the media to the high penalty count against his team and is obviously gambling referees will be loath to punish his illegal double marker defence on rugby league's big day.