Chess clock placement

There could be several factors involved, but from my experience it was so that the tournament director could easily tell at a glance how much time was left on multiple clocks at once, rather than making a circuitous route throughout the playing hall.  All of the clocks on a set of tables would face the same aisle, and thus the TD would just have to walk down that aisle to see if there were any games where a player were running low on time - and that may then require some additional attention in case of any disputes.

  I have a question about playing the black side in a tournament. My opponent (black) chose a board without numbers or letters. I expressed surprise. Can we use my board?,  I asked. He said no; learn to count.  My question: Can I place my board under his board so the numbers/ letters are shown only on my side? Or, can I pull out stickers and put them on the table ( not the board) as an aid to myself? It takes me longer to write the move results and I feel he has an advantage over people who don't play with a blank board- when I'm moving quickly, every second matters.

Black gets to choose the equipment, as long as it's tournament legal - no Simpsons or Star Wars chess sets. Most players would be happy to let you use your board, but black was within their rights not to.  If that throws you off your game, that's too bad. You still have the advantage of playing white!

As for putting stickers next to the board, it would be up to the tournament director to decide whether that's allowed. That decision could go either way. As a TD, my philosophy is "it's okay as long as nobody complains". If your opponent complained about your stickers, I might well rule in favor of whichever player is less of a jerk.

That's the sort of Tournament Director we need!