Ancient Rules Ambiguity: When does "play" begin?

[triangular_cube]

I would lean toward deciding the entry map edges before play begins. This is because the Soviets appear to be in a couple of hedgehog positions. It also appears that the penal units are treated as normal infantry (not being forced to advance on the enemy).

In the rewrite from Edelweiss expanded:

• The penal troops are replaced with infantry.
  
• The entry map edges are specified.
  
• The map area is much bigger.
  

"I would lean toward deciding the entry map edges before play begins."

Yes, I am trying to determine when that is