14: Ban the tick shot

2020.10.24

In any sport, as players get smarter and more skilled and as playing conditions improve, rules get changed. For good reason, too. The rules adopted during an earlier era of the sport were not created for the activity that the sport becomes years later.

Curling, to its credit, seems to have been fairly progressive in regards to adjusting its rules relative to other sports. In good ol’ American college basketball, there are still people who long for the days before the 3-point line and shot clock were added to the game. Indeed, in the 1950’s neither rule was necessary. But the game is different now and would be much less entertaining without those changes.

Fortunately, the curling world doesn’t seem to have a group of people longing for the old days of corn brooms and poor ice conditions. Perhaps there was some resistance to the implementation of time clocks and the free guard zone, but nobody thinks those are a bad idea now.

Something interesting happened two weekends ago in the finals of the ATB Banff Classic. Down 2 with hammer, Kevin Koe elected to blank the seventh end against Jeremy Harty. Like, not blank the end after bailing out of trying to score, but they played it for a blank from the first shot. And Team Harty was willing to oblige. (One of them has to be playing the wrong strategy, by the way.)

Whether it’s better to be two down with hammer or tied without in the final end is the subject of a future post. Spoiler: The latter is better at all but the very highest levels, where it’s a close call. The main reason it’s viable at the elite level is mostly because being tied without hammer in the final end is increasingly a hopeless situation against a competent opponent.

And it’s hopeless because more teams are becoming very proficient at executing the tick shot. The current rules of curling, let alone the original rules, were not designed for a game in which center guards can effectively be removed while in the free guard zone.

Team Koe is the perfect example of this, having converted 32 of 35 situations (92%) where he was tied with hammer in either the final end or the extra end over the past four seasons. There was a time when final-end dominance was solely the realm of elite teams but that’s changing. Check out this breakdown of winning percentage in a sudden-death end with hammer. This is comparing data from the last two seasons to data from the 2017 and 2018 seasons.

The top teams in the men’s game haven’t gotten any better at winning the final end when tied over the last four seasons. Perhaps there’s a theoretical ceiling on how good one can be in these situations and around 90% is it. But the gap between other competitive teams and the top teams is closing. Based on current trends, we could be seeing everyone in the top 100 closing out tied games at a 85-90% rate in three or four years. The women’s game isn’t as deep but we could be five years away from the top 20 or so teams pushing the theoretical limit.

For me, that trend is the most compelling evidence for eliminating the tick shot. The final end, when hammer just needs to score one, is becoming a formality. A tied game in the final end should be the most exciting part of curling, but more and more frequently it is not. It is not entirely the fault of the tick shot, but that has a lot to do with it.

From what I can gather, the resistance to eliminating the tick is that the team with hammer in the final end has earned it. The tick shot is a skill and if you don’t want to lose to a team utilizing it, don’t put yourself in that position. (I’m willing to hear other opinions in the comments.)

I imagine the same argument applied when the free guard zone was being debated. As ice conditions improved, it was inevitable that the peel would become an effective defensive weapon. Pat Ryan’s visionary approach of relentlessly peeling opponents’ guards was a strategy for which the rules of curling were not designed. Still, you could say that anybody playing Ryan merely needed to never fall behind so Ryan’s strategy couldn’t be used.

And while that’s true, it misses the point of why we like to watch competitions. There’s an entertainment aspect that was missing from games in the early ’90’s, as teams that took a lead did the basketball version of stalling before there was a shot clock. Action is more entertaining than inaction and the free guard zone has provided a guarantee that there will be both action and a demonstration of curling skill. You can have both!

When the free guard zone was adopted, nobody imagined that players could become so accurate with the tick shot, despite it being attempted by a few teams almost immediately. But then again, that was decades before the massive increase in understanding of how sweeping can manipulate rock direction. Not to mention how much ice conditions and equipment have continued to improve along with player skill and intelligence.

So now the tick shot looms over games. In the Koe-Harty game, the tick shot was never played, but just the threat of it influenced Koe to adopt a strategy to avoid it being used against him. The game itself was entertaining enough. Harty overcame a 4-0 deficit after two ends to win (thanks, free guard zone). But having a transactional blank in the seventh end is not entertaining and it only happened because Koe knew being tied without last rock in the final end would be a very bad situation.

There’s a debate about whether to standardize the length of curling games to eight ends. I won’t wade into that issue here. But I think I could find near unanimity against shortening the game to fewer than eight ends. And yet, that’s what the advancements in using the tick shot have done.

The Koe-Harty final ended up sacrificing an end of action when both teams accepted a blank in the seventh. And the seventh end is the most blanked end in high-level curling after the first. If you’re tied with hammer in seven, blanking the end is very close to a guaranteed win for some teams. An eight-end game becomes six ends in cases where the score is lopsided but thanks to the tick shot it often becomes six ends even in a close game.

I get that the tick shot is a skill that most normal curlers lack and there is some appeal to seeing the best teams make it. But the same could be said for the peel back before the free guard zone was implemented. Like the peel, the tick is a skill that leads to less interesting curling when used with impunity.

But also, banning the tick shot wouldn’t eliminate hammer’s advantage in a sudden-death end. It would just reduce it to something that would increase the chance that real curling breaks out in the final end. Which in turn would add to the chance the real curling occurs in the end before that as well. Blanking with hammer in a tie game is a different decision if your chance of winning in the eighth is 75% instead of 90%.

I think it’s inevitable that there will be a rule addressing the tick shot in the next decade. As more teams approach a 90% success rate with hammer in sudden death, more teams will adopt Kevin Koe’s philosophy of preferring to be two down with hammer to being tied without. And incentives at the end of games will get influenced in other ways that make tight games less exciting than they should be. The free guard zone created a more interesting sport nearly 30 years ago and it’s becoming apparent that a restriction on the tick shot will have a similar affect.

User comments
  1. Curling Robots · 2020.10.24 · 5:48 am

    Agreed that teams are getting too good at the tick shot and something needs to be done. At the same time, it’s a skill that some leads are better at than others, and we don’t think banning them altogether is the best solution at the moment (though maybe in the future). The Champions Cup banned tick shots in the 8th/extra ends on rocks touching the centre line—an interesting start to a movement of eliminating tick shots altogether? A few (not many) teams have occasionally played ticks on corner guards, but it would be interesting to see this skill develop before banning all ticks.

  2. Kevin Palmer · 2020.11.11 · 10:19 pm

    Per my last Curl With Math article, it’s more than just the math and poor odds. Truth is, a tied baseball game in the final inning is closer in WP to a team 1 up without hammer in curling. And a team in baseball up 1 run is more like a tied curling game. But the entertainment value of the 1 run ballgame is much higher. In curling, a team makes both ticks and change the channel. In baseball, even the final batter can tie the game with 2 strikes and two outs. It’s even possible that eliminating the tick won’t reduce a team’s odds of losing much at all, but there is little doubt it will greatly vary the shots called and extend the tension and drama deeper into most ends.

    1. Kevin Palmer · 2020.11.11 · 11:38 pm

      To clarify. WP meaning Win Probability

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