nice article:
http://www.thestar.com.my/Lifestyle/Viewpoints/Big-Smile-No-Teeth/Profile/Articles/2014/10/05/Modern-strategy-games-versus-chess/
Compare this to a modern strategy game like Company of Heroes 2. There are dozens of different units of different sizes with a multitude of capabilities for different situations. Units are designed to counter each other, but given the random variations in the game due to things like cover, elevation, and the realism of random factors of combat, any unit can overcome another.
The players don’t know where the enemy is unless they are actively doing recon, and the other players’ units are definitely not known as requisition of new units is to either surprise or counter the enemy.