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Tuesday, November 8, 2011

Is 5 the Magic Number?

How about that 5-Rock Rule?

The World Curling Tour’s Player’s Association has decided to trial a 5 rock rule at the upcoming Grand Slam event in Kingston, December 14 to 18th (which one is it again, Masters or Open?)  The rule would make the 4th rock of the end (thrown by team with hammer) now eligble for “free guard zone” status, unable to be removed by the opposing team until after the 5th rock, most likely the 7th rock of the end.  Essentially 4 rock means that 3 rocks are safe from removal (if put in the correct location, between house and hogline) and subsequently 5 rock rule means that 4 rocks are now safe from harm.  Confused yet?

Though I applaud the WCT and their PA for doing what many other athletes would like to do, which is have a direct influence on their sport (ask the NBA PA how they feel these days), I don’t believe this new version of Curling will have a significant impact and may in fact result in the opposite desire than is intended.  But perhaps we need to examine what it is trying to do exactly.

Firstly, is there a desire is to create more offense?  That comes with some risk.  Curling is a game that actually needs less offense to ensure a close game, but needs scoring to be exciting.  It is a game where being 3 or more down with hammer or 2 (or even one) down without  becomes no longer interesting, and progressively so as the ends tick away.  If more offense opportunity creates higher scores early, teams will then be apt to stay out of trouble, let the team behind take chances, and capitalize on their risks (when they fail) and end the game even earlier.  As boring as it sounds, a classic game of no free guard zone which is blanked for 9 ends and played tied in the 10th is closer (though clearly not as exciting) as a game where a team cracks three early, gives up a single and then score two (and after three ends we are off to the other sheet for coverage, hopefully).  Imagine most any boxing match with Bernard Hopkins, grappling, pacing, counter punching and plodding along until he wins on a decision as opposed to a Haggler vs Hearns with an explosion of attack until only one stands after a few short rounds.  So my position is, more offense is not necessarily good.  Perhaps what we mean to say is…

Do we want to keep games closer?  Similar to the original Pole Position on Atari, do we want the cars that are behind to have more speed than those in the lead so we ensure a close race?  As I stated above, even with the 4 rock rule a team can quickly move from a close game to a position of Dominance with a quick three and then hold their opponent to 1.  So can a 5 rock rule allow a game to stay closer, allowing for more comebacks? 

I traditionally felt 4 rock was the “fairer” rule to the old 3 rock, in that some edge was given to the team without hammer (2 rocks protected, versus 1), to offset the large advantage the team with hammer is given.  Despite this edge however, teams still only win 25% of the time (closer to 20% in Grand Slams) when tied without hammer and one end to play.  So can 5 rock change this?

I believe the answer is yes and no.  The one situation I like, and an 8 end game perhaps stresses this situation, is the fact the hammer team is, early in a game, most likely behind.  For example, if I start without hammer, there are three most likely scenarios, assuming two equally matched teams.  In order of likely occurrence: my opponent scores 1, my opponent scores 2 or I steal 1.  Threes and steals of two or more can obviously occur, but are less likely.

In each case there are now 7 ends left in an 8 end game and, though this may seem obvious, the second end is the only time in a game we are 100% assured the team with hammer is behind.  The third end is also very likely to have the team with hammer either tied or behind.  The most likely scenario where we have hammer and the lead in three is to take 2 in the first then force my opponent to one.

In the case where the team with hammer is behind, the 5th rock must be an advantage.  I don’t know how much at this point and, some argument could be made that if the play moves to the centre there would be very little impact anyway, but let’s not dispute there must be some gain in protecting one additional rock.  In these early situations I support the rule as a (however slight) gain for the team that is behind and concede it just might help create a closer contest during the early ends.

So what about later in the game?  Today, tied in the final end, the team with last rock has a significant advantage (75 to 80%).  5 rock is not going to help the team without hammer in that situation.  If you are one down with hammer in the final end, stats show a 40% chance of winning the game.  Here, this rule could bump up that percentage but doubtful how much and, frankly, 40% is already competitive and engaging to the viewer.  It’s rare that a one point lead in the final end doesn’t create excitement, so why change for that?  Maybe if we are two down with hammer coming home, our chance might increase from 12%, but realistically to what?  Even if you get your deuce to tie (considerably more likely than a three), you are in the same spot tied without hammer in an extra end, and no advantage with this 5th rock rule.

Let’s move to next to last end.  The 7th end (or the 9th end in a 10 end game), has often provided some of the most interesting situations since curling moved to free guard zone.  Take for example the GP Grand Slam Quarterfinals, where Howard, one up against McEwen and facing a single opponent stone on the back four foot, considered freezing to try and force a single.  What changes with the 5 rock rule?  In a tied game, the team with hammer is not going to be forced into any different situation than today’s rules.  They may elect to more aggressively attempt a deuce, at the consideration that being one up in the last end without hammer is less advantageous, but I doubt the thinking will change drastically.  Today, most teams recognize a blank is less likely and the team without hammer is forcing the issue to have a score (be it a steal or surrender a single).  When a team with hammer is one down, there becomes even less incentive to score a deuce, as they would have most likely greater than 40% chance if they remain one down with but their chances when tied without hammer doesn’t increase from the rules today.  O the flip side, the team one up without in 7 or 9, is just as likely to be aggressive, risking a deuce at the hope of stealing or forcing the opponent to a single.  They may be slightly more aggressive, but this rule doesn’t help them in that regard.

So where does this leave us?  If the top curlers want to try it, I support the effort and wish them well.  Though I suspect the impact will be hardly noticeable, perhaps it will keep a few games from getting less competitive early and make for more dramatic contests.  I doubt it.

Now did anyone ask what is wrong with the game as it’s played now and have we agreed it needs to be changed?  That is something I’d be interested to hear more about and would suggest that simply adding another protected rock will not repair a game if it simply does not provide enough excitement and drama for its audience or its players.  For that we may need to add some physical contact to the game, though no head shots obviously to avoid concussions and excessive fines.

Good luck curlers and here’s to 6, 7 and 8 rock free guard zone (which would of course be 5, 6 and 7 protected rocks) sometime in the near future.


  1. Kevin,

    Always like your articles. Do you have any stats on the winning percentage of a team once it is ahead by two? Or percentage of come from behind wins on the WCT?

    It seems like the strategy when ahead is to peel the corner, and then look for a double when the hammer stones are exposed - the hammer can get a point, but then control of the game is gone. And I would think it would change the "one down with" percentage enough to affect strategy, fwiw.


  2. Down by 2 with hammer, a team wins as follows (from 7 ends remaining down to 0 ends remaining):.261/.246/.242/.211/.193/.150/.117

    Down two early is very close to being tied without hammer coming home (25%), and then becomes actually worse during the later ends.

    As far as come from behind wins, we'd have to combine all the stats of each situation, perhaps I'll get to it later this year.

    Thanks for your questions!

  3. Kevin:
    Want to make the game more offensive???

    Change the blank rule to read: "if a team blanks an end, they would lose last rock advantage in the following end".

    Now everyone is going for the deuce with last rock as they are going to have to take one anyway....if they can.

  4. What is the hammer worth depending on which end it is? I suspect it is between 1.1 and
    1.2 points. What are the odds of stealing depending on the end? What are the odds of scoring 2 or more points depending on the end?