This is the first post in a series of blogs where I'd like to engage the Sudoku community in various discussions relating to the World Sudoku Championship
For this first post, I'd like to talk about points scoring at the WSC.
The traditional model of the WSC goes like this. The organisers will fashion together a set of puzzles of various types, and then group them into a number of rounds. The puzzles will be test solved by a number of testers, and their times will be aggregated, and each puzzle will consistently be assigned a number of points according to how they tested. For example, if we have decided each championship minute should be worth 10 points, a 2 minute puzzle will be graded as being worth 20 points.
I think there are a few things worth discussing here, but the first I'd like to concentrate on is that there are Sudoku puzzles, and there are Sudoku puzzles. For the former, read things that are generally well known and recognised as Sudoku, your classics, diagonals, extra regions, odd/evens, irregulars and killer. For the latter, you are almost encroaching onto WPC territory with things like Greater Than, Kropki and Skyscrapers - all of which exist as standalone Latin square puzzles without Sudoku's trademark Third Constraint.
At every WSC round there is inevitably (at least one) long round, typically 45 minutes to an hour, or even longer, full of challenging Sudoku variants (see also the Daily League project) that if you were to show them to the general public, you could be sure of a reaction of bemusement and bafflement. Due to the length and difficulty of these rounds, they are usually the rounds that score the most points and decide who finishes where in the classification.
As such, the winner of the WSC tends to be the best all-round solver, combining a mix of WPC skills and raw Sudoku solving speed.
I think the balance used to be weighted much more to WPC skills than it was. For example, in 2006 Rachel Roth-Huber bested David McNeill (and my good self!) at the Times Su Doku Championship. But the following spring at the WSC in Prague, David - a WPC veteran - finished 4th, compared to Rachel who finished way back in 66th (for reference, I was 45th). This is not to say David does not possess exceptional raw Sudoku solving speed (he certainly does), but I would certainly have forgiven you for expecting the gap between the two at the WSC to be a little closer.
These days, the WSC play-offs form a large (although not perfect) overlap between the best all round solvers and the quickest classic solvers, which I think is probably testament to the fact that Sudoku solvers have generally improved their puzzling skills.
However I'd like to finish by asking my audience to question this paradigm. What if it were decided to place (for the sake of argument) a 0.8 multiplier on the long variants rounds at the WSC, to place more emphasis on the friendlier, more publicly recognisable puzzles? Would this be a good idea? And do you have any other thoughts regarding WSC scoring?
I'd love to know everyone's thoughts on this, no matter what kind of solver you are!