Originally posted by SwissGambit At one time, the rules did not specify that you could only promote to a piece of your own color. Several 'joke' problems exploited this obvious loophole; perhaps this was one of them.
this nitpicker ( we germans prefer "currant pooper"😉 lawer finding, that you are only allowed to promote to a piece of your color, is not so old.
I think thats 30 or 40 years ago, like the "very long castling" or Pam-Krabbé-castling.
So Tartakover cannot be the author - he died 1956