WCC Editing Project:
"The Strange Tale of how <Vasily Smyslov> got Fifteen Extra Minutes on his Clock without Realizing it"
Botvinnik:
<"...on one occasion in our match the arbiter Opocensky had to intervene; this occurred during the 18th game. Soon after the opening Smyslov's clock stopped, which was noticed by the demonstrator only some fifteen minutes later! More precisely, the clock did not stop- it continued going, and only the minute hand stopped, and so neither I nor my opponent noticed this, since the clock continued ticking...During play a second, electric chess clock was in use, enabling the spectators to observe the situation on our clocks. This electric clock was operated by the demonstrator, and it was he (with a delay of fifteen minutes) who drew the arbiter's attention to the fault in Smyslov's clock.
Of course, Opecensky ordered that the faulty clock should be replaced. <<<In so doing, however, he set my opponent's clock to the same time as had been shown by the faulty clock! To my bewildered question, the arbiter replied that there was no mention in the match regulations about supervisory electric clocks, and therefore he couldn't put Smyslov's clock forward, although, essentially, it was clear how long the clock had stood still.>>> I immediately accepted the arbiter's decision, although I considered it incorrect.
I decided not to approach Smyslov directly; he was so engrossed in the position that he did not notice either our discussions, which took place at the other end of the stage, or the change of clocks itself, otherwise he would undoubtedly have asked that his clock be put forward...">
-Mikhail Botvinnik, "Botvinnik's Complete Games (1942-1956) and Selected Writings (Part 2)." Ken Neat, transl., ed., (Olomouc 2012), pp.29-30