# Chess and cheap ways to check day to day variance in cognition

Lately I've been playing chess. I'm not very good at it. I started because our four-year-old got into it, and I preferred not to lose to her before she had earned it. I play online on chess.com, which has instantaneous matchups with strangers at approximately your level; I mostly play 5-minute timed games, where each player has a 5-minute clock for all of their moves and loses if they run out of time. 

Doing this every day for a couple of months made some interesting patterns obvious. Firstly, I have good days and bad days, rather than just winning or losing mostly at random at my competence level.   
  
Bad days are predicted by some of the things you'd expect, like poor sleep, high stress, or emotional distraction, but sometimes I have a bad-day-as-measured-by-chess when I wouldn't have predicted it, or (more rarely) a strikingly good day when I thought I was likely sleep deprived.  
  
Secondly, playing chess on a good day versus on a bad day allows a lot of access to the feeling of being slightly smarter or slightly stupider than usual. In general, I think my ability to do high-level cognition varies a lot day to day and even within a day, but it's often really hard to tell if I'm blocked on a problem because I'm a little low on ability to think about it; usually, a problem will be different from other problems in a bunch of ways, and it's hard to tell how much of the difficulty is that I'm fatigued/distracted/whatever.   
  
With chess, you're basically solving the same category of problem every time, with instantaneous feedback about whether your solution was any good, so I get unusually good felt-sense of where I would normally have seen something, but this time missed it, or alternatively where options and counteroptions are coming to me unusually quickly and have unusual depth and clarity.   
  
Thirdly, having a good day at chess seems pretty strongly associated with having a good day at high-cognition-requiring tasks in general. In fact, it seems like a *better* predictor of this than asking myself 'do I expect to be good at cognition today?'.   
  
On days when I do well at chess, I'm also likely to succeed at reading a complicated paper I previously bounced off because it was too hard, or at writing an article that has been blocked on loading all of it into working memory, or at having productive new thoughts if I dwell on an old problem for thirty minutes. I am *not* more likely to succeed at doing my taxes or other tasks that are motivation- rather than cognition- bottlenecked.

This could, obviously, be a self-fulfilling prophecy, or a placebo effect, but at least for me it makes playing chess a moderately valuable thing to do; in about ten minutes I can get a readout on how well my brain is working, and figure out from that which of my priorities for the week make sense to work on.  
  
I am wildly uncertain how much this would generalize to other people, but it seems like a cheap experiment. Some suggestions, if you want to try it:  
 

*   I do 5-minute games now, but for the first two months I did 10-minute games, and found the 5-minute ones pretty bad for me: I wasn't good enough at thinking about chess to think at all in the shorter time setting, and was just reflexively making moves on instinct, which is not very useful or interesting. Over time, I compressed/cached some stuff and now I get about the same experience from 5-minute chess I used to get from 10-minute chess. I recommend starting slower.
*   There's tons of advice about how to play chess - which openings to use, which countermoves to memorize for common openings by your opponent, etc. Don't learn any of it. Those things increase your ranking at chess, but the thing that's interesting here is chess as an environment in which you can see your brain function, and those things don't particularly help with that and are a time-sink of fairly arbitrary size.   
      
    You'll learn over time by losing and going 'okay, I'm not going to let that trick me again'. Your rating will probably eventually flatten out lower than the ratings of people who spend the time studying the meta, but that's not what you're using this for. Learn enough stuff about how the game is played that you have an idea of what criteria you should be using to evaluate potential moves - that is, "how do I know if this move leaves me in a stronger or weaker position" and then try to resist the urge to memorize openings or anything like that. 
*   chess.com offers more feedback than just "did you win the game or not" - in particular, there's an option to go through the game move by move and see what the smartest move would have been, and to revisit decisions you made that were particularly bad and try to make better ones. I do this sometimes.   
      
    They also rate your game by how closely your play adhered to 'perfect' play (what the chess engine would've done), on a 0 - 100 scale; unfortunately you can't take this number too literally as a 'how clever am I today' number because things like 'was there a long endgame where both sides had a bunch of forced/obvious moves' affect the scale a lot. I still use it for data, though.
*   If you try it, or if you already do this, please comment with: did you notice day to day or time-of-day variance in how well your brain seems to be working at chess? did it track with variance you'd noticed in other contexts? did it predict anything else?