Like in chess the ending is the most important phase of the game, the river is also the crucial phase in NL Holden.
The reasoning behind that is that in the river the pots are bigger than in any other street. So good decisions are crucial, and any bad move will cost us much more than a bad decision in the turn, the flop, or preflop.
The first game I study like a science was chess, and today I believe the following analogy Between Holden and Chess:
Pre-flop = Opening
Flop and Turn = Middle Game
River = Endings