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Tim Krabbés blog is recommended for this type of question and in general: https://timkr.home.xs4all.nl/chess2/minor.htm

I had known of stalemate (both causing and preventing it), but there are others as they mention there.

One other I think I have read about (I do not entirely remember) is that someone promoted to rook because promotion to queen would have taken more time due to not having a extra queen to promote to so they would have to go to another table to borrow it (or ask the tournament officials for it).


Are upside down rooks not allowed to substitute as queens?

As far as I know, it doesn't count. But, I looked it up. Apparently, it is allowed in USCF but not FIDE.

There is also nice discussion of the beautiful and practically relevant "Saavedra position", which does have an under promotion to a rook. https://timkr.home.xs4all.nl/chess/saavedra.htm

>Bruce helped the young athlete understand his movements in a way that seemed to decelerate time. “Bruce showed me how to harness some of what was raging inside me and summon it completely at my will. The Chinese call it chi; the Japanese, ki; the Indians, prana—it is the life force,” he said. “I was quite amazed to find, after working with Bruce, that when I really had my presence of mind, when I did control my life force, that’s what I saw, things coming at me in slow motion with plenty of time to get out of the way.

Seemingly we are learning here something new about Bruce Lee, that outside observers can't understand, most notably western ones. This decelaration of time also happened to me two times spontaneously, when I was attacked on surprise, hence I believe this verbatim. In both cases, that got me plenty of time, to decide what to do and was able to save myself without a scratch. However it never occurred to me,that that had something to do with my Chi force...


I have had the same experience when attacked. A football hooligan smashed a bottle on my head from behind. Time slowed down. I turned around and could see everything he was doing in slow motion and I was completely calm. I knew what he would do before he could do it.

I am not a fighter or physically brave, but I completely disarmed him, put him in a headlock and threw him to the ground.


Josh waitzkin breaks this down really well in his book the art of learning.

He's a chess champion and push hands champion and discusses how to learn. Basically as you become and expert in something you learn to pay less attention to the surrounding environment and only focus on what matters, which allows you to see it in "slow motion". This applies to chess champions where masters eye movement focuses on a much smaller part of the board than a beginner, and also in push hands or BJJ where experts fighting for a tiny bit of grip change is what matters but a novice might just see the whole body not moving or doing anything that matters.

Very worthwhile read.


Interesting, I wonder if this is the thing that happens to while playing this videogames. At some point after hours (30+) struggling against the same boss,you realize you see everything in slow motion,at that point you know it's the end, you mastered it. I literally say "ok it's done, time to defeat it".

Is this Chi

I always thought of it as muscle memory, the movement becomes so ingrained in your body that you can focus on things at a higher level. Keep going up the levels and at some point everything looks like trivial details


Based on my own experience, it's nothing like chi or something supernatural. The repetition has lowered the uncertainty of the thing you're trying to do, to the point it's easy to do if you focus.

That's it, experience and focus. Even if you mastered something, someone can keep distracting you and you will find it returns to difficult without focus. Even if you focus a lot, hard things have to be repeated to master them.


I think Senna biopic mentioned him saying road moves in slow motion when he gets into the groove.


Yep! It’s possible to become a much better drive with track seat time. I’ve noticed that after 4 years of HPDEs, corners seem slower and I can place the car much more easily where I want.



It's called bottom up processing and time slowing down is a side effect of that

https://en.wikipedia.org/wiki/Pattern_recognition_(psycholog...


There is no such thing as Chi force, so it wasn't that. The perception of time is malleable though.

See https://www.psychologytoday.com/us/blog/sense-time/201707/th... and tons if other articles.


It's super interesting, I have had it the most in a car accident saw my seatbelt snap and slide off of me like it was a sleepy snake, watched the stuff in my backseat get hang time that would have made MJ jealous, and thankfully managed to not die.


I had something similar happen when I was a passenger in a car accident. I had been asleep and woke up just before the impact. I watched the car's front end crumple in slow motion and was able to protect my head and "roll" with the collision to come out unscathed.


I always assumed the slowing down of time effect was induced by hyper alertness from the dose of adrenaline you get when in trouble.


Personally I think our eyes and senses input a lot of information then our brains discard what it feels is unnecessary without processing it. But some people can train the brain to process more of the information like a formula 1 driver.


You might want to study Bioenergetics - https://en.wikipedia.org/wiki/Bioenergetics and Bioenergetic Systems - https://en.wikipedia.org/wiki/Bioenergetic_systems if you want to understand Prana/Qi/Chi/Ki in the modern scientific context.

Also see Guy Brown's The Energy of Life: The Science of What Makes Our Minds and Bodies Work.


You linked to articles describing actual biology, not anything like "Chi".

I pointed you to the mapping of the concept of Prana/Qi/Chi/Ki in today's scientific context. They were framed in a different cultural context with a different concept of "Science" and it is up to you to map them to concepts in modern science.

For example they had a different model of Anatomy/Physiology in spite of the fact that they were aware of the various circulatory and nervous systems. Their approach was more holistic and empirical rather than reductionist and analytical. So even though you might not have a one-to-one correspondence to concepts in modern science there is enough studies/research done to establish that there is something to those ideas and hence their various practices (especially Yoga and Acupuncture) are now used in Healthcare to treat various ailments.

Some resources;

1) Perception of Subtle Energy “Prana”, and Its Effects During Biofield Practices: A Qualitative Meta-Synthesis - https://pmc.ncbi.nlm.nih.gov/articles/PMC10498708/

2) The Science of Tai Chi and Qigong as Whole Person Health-Part I: Rationale and State of the Science - https://pubmed.ncbi.nlm.nih.gov/40091656/


no, chi and centrifugal force do not really exist. But because everything we percieve is essentially a metaphor, a model of reality, sometimes chi or loosy goosey uses of the word 'energy' really can be a valid heuristic for the things that you can do to optimise your 'ability to do work'. As long as you remember its a vague, subjective, context restricted heuristic, and don't try shooting chi bullets, I say max your chi flow friend.


As a kid I had this happen in sports fairly frequently. What feels like seconds is really a fraction of a second. It helps a lot. I'm not sure I would ascribe it to some mystical thing like chi or ki, just something funky going on with our brains.


I wonder if we should take seriously the idea that the brain can process information faster in emergencies, rather than this just being our perception. After all, we know our neurons work orders of magnitudes more slowly than transistors, so there would seem to be plenty of room for increase. Obviously there must be some biological reason why we're not usually faster, but perhaps it doesn't preclude a temporary speedup.


The explanation is, that the number is _not_ the infinite string of characters, but the sum of the scaled digits of the string. This sum is defined as the limit of the partial sums. In Germany, you can understand this in high school.


And why does that change anything? No, it comes down to the definition of "=", which is not explained in schools.


https://m.youtube.com/watch?v=qJZ1Ez28C-A I had learned about the double slit experiment in school, but in my mind it was something of a theoretical construct. This veritasium video demonstrates, that quantum waves are very real and tangible. This is how physics should be.


> It's one of the single biggest misconceptions ever, it gets repeated endlessly

FM Roese here (best DWZ 2399). I agree, figuring or even conjecturing that Fischer overlooked 30.g3 is totally insane. However he also did not saw the theoretical draw, this strikes me even more off. He never opened up about his idea, so in all likelihood he calculated something very stupid.

> if you plug it into an engine, it shows an equal evaluation

They criticized this argument rightly, but many basically repeated your mistake in the process of doing so. All engines use some evolved adaption of iterative refinement, be it either "Iterative deepening" (of an alpha beta search) [1] or "UCT" [2]. If you post computer evaluations you should at the very least give the reported nominal search depth and the engine name and version, otherwise you are just asking for trouble. On computer chess fora [0] they often post the whole log file bluntly.

[0] https://www.talkchess.com/

[1] https://www.chessprogramming.org/Iterative_Deepening

[2] https://www.chessprogramming.org/UCT


Facility score may IMHO be understood as some statistical measure of tactical involvement. It has really nothing to do with the established and important concept of weakness in chess, which looks at significant static features of a position. For example in the position from figure 1, white's pawns on the queen side are all weak, especially c4. Also the black squares around the white king are weak. After 1...exd4 these weaknesses are pronounced sharply. Considering fragility score, I see nothing that points towards these weaknesses. a4 and b6 are not attacked, hence ignored. c4 is attacked once and defended once, but there is no trajectory over it. Weak squares are not considered. If we look at the knight D4, it's BC score may tell us, that after taking it with a pawn, which can be done in two different ways, the bishop e3 is hanging, hence we gain a tempo, which is significant, also f3 is weaker (noise) and bishop e6 is not under pressure any longer. Hardly something which convinces to identify the key moment, but may be useful in a statistical sense. Nevertheless it appears to be an oversold complexity measure.


1..c1Q?? 2.Ba3+ loses on the spot, hence it is deduced easily that 1..c1N+! must be the best try. Consulting an online table base [1] shows that the resulting position is a ”blessed draw”: White can still mate, but not in time to evade a 50 move draw claim.

[1] https://syzygy-tables.info/?fen=8/6B1/8/8/B7/8/K1pk4/8_b_-_-...


> mid = ((unsigned int)low + (unsigned int)high)) >> 1;

Also not correct if the sum overflows.


It can't overflow - max_int+max_int < max_uint


This reasoning is correct but still has to assume that both indices are non negative, which is reasonable.


So does the bitshift cast the result of the addition to an unsigned int? I am not so familiar with Java.


To put it mildly.


Tasteful and elegant, but somewhat thought provoking at the same time.


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