Sunday, August 27, 2006

How Many CTS Patterns?

Today I started a project that should allow me to estimate the number of different patterns at CTS. My first session, of course, does not give me any order of magnitude yet. But, as I hope, with more sessions this should be possible. I had decided to have a closer look at each problem after having done it, but I could not help looking closer while solving, so I lost about 30 rating points. But this does not bother me at all, because I'll gain them back later.

I did 50 CTS problems, 49 right, 1 wrong, on an average level of 1415. I identified and listed every pattern. The 50 problems presented a total of 69 patterns or 42 unique patterns. This means that every pattern occurred roughly 1.5 times on average.

Here is the preliminary pattern hitlist, ranked by number of occurrence. The first one was presented 5 times, the last one twice. I hope the names to be more or less self-explanatory. The mates are always from the eight basic mates presented by King of the Spill.

Capturing Guard
Capture With Threat
Chasing Guard
Discovered Attack
Chasing Guard With Check
Frontal Queen Mate
Pinning Piece of Higher Value
Bishop Fork
Oblique Queen Mate
Overworked Knight
Promoting to Queen
Queen Fork
Rescue By Trade
Trapping Bishop


At 1:54 AM, Blogger wormstar said...

maybe you should save a sufficient amount of problems, like tempo has done, and count the patterns in one session. could be less work? tempo probably has such a file already?

I'm also wondering if the average number of patterns per problem increases with rating? you should probably do a couple of comparative batches with low rating and high. if there's meaningful difference, you'll probably have to sample all rating ranges to avoid bias...

is there really only 1.5 patterns per position? I would've guessed 3-4... or are you only counting the ones that are part of the solution?

At 2:02 AM, Blogger Loomis said...

This is an awesome project and a clever idea you've had in your recent posts. To list the tactical motifs will produce quite an interesting result. Either you will find there are a seemingly limitless number of techniques that become more complex or that there are a finite number that can be combined in complex ways. Either result would be quite striking.

Since it's possible to list the problems on the site ranking them by rating, it would be straigthforward to compare a set of problems of one difficulty level with another. I have a feeling that the more difficult problems will simply be complex combinations of the simple motifs. Although one reason problems can get a high rating is through decoy motifs. For example, in some problems there is a really good looking (potential) pin that has nothing to do with the solution.

At 8:40 AM, Blogger Mousetrapper said...

Wormstar, excellent idea, anyway, a better idea is not to use competition mode for such an analysis but rather search for the problems in the CTS database, ordered by ranking ... I used only a set of low-rated problems, hence the low density of patterns. I did count only the significant ones, leaving out simple captures or threats that were also possible but not a part of the solution.

Loomis, I suspect that there are some hundred basic patterns that can be combined in complex ways. I am looking for a more sophisticated theory first, before doing more empirical studies.

At 9:52 PM, Blogger transformation said...

this is very, very, very smart. awesome! thank you for your comment today at my post. i am just getting to know your work, but whatever the dispostion, sounds like you are sharp as a tack!

i know what you mean about those 90% from old 78 and 80%--when i do 85% or 83%, i sincerely feel like i botched my session. not many bloggers who are at CTS seem to understand why i care so much about this, but if chess is not very carefull, then what is it?

mind you, i did not say few APPRECIATE what im saying about THAT, just understand % or value it... as ive said many times: so much talk of ratings.

it sounds like you are doing cognitive mapping almost.

when i was managing only 10 million dollars, i made carefull maps of what the distribution of assets would be at 40m, and when i got there, and long after, when i looked back two years latter, was astonished to see i got what i planned for if not exactly, then VERY close to.

best regards, david


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