was common to see street and city names, names of months or days of the week, names of famous chess players, names of audience members, names of movie stars or TV personalities, telephone numbers and addresses, birth dates, serial numbers from bank notes, etc. After concluding his problem solving challenges on the demonstration board, Koltanowski would turn his back on the audience and examine the chalk board for three or four minutes. Then he would seat himself with his back to the board and ask for any audience member to call out a square; for example, e4. He would recite from memory the entry in that square as an assistant crossed it off with a chalk mark. Making imaginary knight-moves through his re-entry sequence, Koltanowski would recite the contents of each square as the knight landed on it. As amazing as this performance was, if time permitted afterward, Koltanowski would occasionally demonstrate his mental grasp of the board by reciting the information contained in the squares by rank or file, or even the two long diagonals. He occasionally performed the tour on two boards simultaneously. In Palo Alto, California, he conducted his performance on three chalk boards, jumping the knight back and forth between boards mid-move, until all 192 squares were completed. He made two errors and immediately corrected himself both times. At the time of this performance, Koltanowski was 80 years old. References External links Chess Space obituary "Grandmaster Of Chess, George Koltanowski", 2 July 2000 Edward Winter, Koltanowski 1903 births 2000 deaths Belgian emigrants to the United States Belgian people of Polish-Jewish descent Belgian Jews American chess players Belgian chess players Chess grandmasters Chess Olympiad competitors Jewish chess players American chess writers Chess arbiters Chess officials San Francisco Chronicle people Writers from San Francisco 20th-century American non-fiction writers Businesspeople from Antwerp 20th-century American male writers American male non-fiction writers 20th-century chess players