user26072: I was recently leafing through Pritchard's Encyclopedia of Chess Variants when I noticed that the variant Hand and Brain which has recently become popular, in which one player states the piece to the moved ('Brain') and his partner then decides the move with that piece ('Hand'), is missing.
It would be in Chapter 34 of the 2007 edition following Tandem/Alternation Chess, since Hand & Brain is the only other variant which uses 1 standard board, standard pieces, and standard rules, but permits team play.
What are the origins of Hand & Brain chess? I'm interested to know what the earliest recorded mentions of the variant are by this name and also by any older historical name.
N.B. The earliest mention I can find is on Alexandra Kosteniuk's blog dating to February 2013: http://www.chessblog.com/2013/02/. The name and rules already seem to tie up exactly with the variant we recognize today, suggesting that the variant was at least somewhat known by then.

user31663: A lot of online sources and videos online were from 2018-2021, as it was very popular then, so it is very tricky to find anything
Some say hand and brain chess was inspired in really fun videos from Eric Hansen, Daniel Rensch and Anna Rudolf, but this it isn't that old here, so I conclude that Alexandra Kosteniuk's blog is probably the earliest mention of Hand and Brain chess.
I have searched for the exact phrase "hand and brain chess" and "hand and brain", but all 3950 of the results on google were quite recent, oldest found is the below link (2016)
(Still looking at the moment)
Feb 2016 mentioning of Hand and Brain chess
Reddit question of the origins
There is a possibility that Hand and brain chess is somehow related to Team chess, where the control over pieces on the board are shared among the teammates who are not allowed to communicate with each other during the play other than via valid moves.
Another possibilty, but unlikely, is Smess chess, where arrows on the board indicate where pieces should move. (This variant uses fairy pieces and a 8x7 board)

26072: <p>I was recently leafing through Pritchard's <em>Encyclopedia of Chess Variants</em> when I noticed that the variant Hand and Brain which has recently become popular, in which one player states the piece to the moved ('Brain') and his partner then decides the move with that piece ('Hand'), is missing.</p>
<p>It would be in Chapter 34 of the 2007 edition following Tandem/Alternation Chess, since Hand &amp; Brain is the only other variant which uses 1 standard board, standard pieces, and standard rules, but permits team play.</p>
<p><strong>What are the origins of Hand &amp; Brain chess?</strong> I'm interested to know what the earliest recorded mentions of the variant are by this name and also by any older historical name.</p>
<p>N.B. The earliest mention I can find is on Alexandra Kosteniuk's blog dating to February 2013: <a href="http://www.chessblog.com/2013/02/" rel="nofollow noreferrer">http://www.chessblog.com/2013/02/</a>. The name and rules already seem to tie up exactly with the variant we recognize today, suggesting that the variant was at least somewhat known by then.</p>
 31663: <p>A lot of online sources and videos online were from 2018-2021, as it was very popular then, so it is very tricky to find anything</p>
<p>Some say hand and brain chess was inspired in really fun videos from Eric Hansen, Daniel Rensch and Anna Rudolf, but this it isn't that old <a href="https://www.chess.com/forum/view/fun-with-chess/play-hand-and-brain-chess-online-http-handandbrainchess-com" rel="nofollow noreferrer">here</a>, so I conclude that Alexandra Kosteniuk's blog is probably the earliest mention of Hand and Brain chess.</p>
<p>I have searched for the exact phrase &quot;hand and brain chess&quot; and &quot;hand and brain&quot;, but all 3950 of the results on google were quite recent, oldest found is the below link (2016)</p>
<p>(Still looking at the moment)</p>
<p><a href="https://matthewsadler.me.uk/attack/hand-and-brain/" rel="nofollow noreferrer">Feb 2016 mentioning of Hand and Brain chess</a></p>
<p><a href="https://www.reddit.com/r/chess/comments/nophmr/the_origins_of_hand_brain_chess/" rel="nofollow noreferrer">Reddit question of the origins</a></p>
<p>There <em>is</em> a possibility that Hand and brain chess is somehow related to <a href="https://en.m.wikipedia.org/wiki/Team_chess" rel="nofollow noreferrer">Team chess</a>, where the control over pieces on the board are shared among the teammates who are not allowed to communicate with each other during the play other than via valid moves.</p>
<p>Another possibilty, but unlikely, is <a href="https://www.chessvariants.com/other.dir/smess.html" rel="nofollow noreferrer">Smess chess</a>, where arrows on the board indicate where pieces should move. (This variant uses fairy pieces and a 8x7 board)</p>
