When does the ending start?

While the start point of openings is pretty straightforward (Move 1!) and the middlegame starts when your memorisation of opening theory runs out, the start point of an ending can be a little trickier. When I was writing chess engines (which evaluate positions differently in the ending), I had an arbitrary rule that the ending started when there was less than a Q+R in material (excluding pawns) for each side. The other possible definitions include "when pawn promotion becomes a goal" or "when the king can move about without the risk of getting checkmated".
It is the last definition that I use most often when coaching. Of course it does depend upon on recognising all the threats in the position, and there are plenty of endings that have ended in checkmate.
A kind of counter-example (in a different sense) turned up from last nights first round of the London Chess Classic (the reason why this post is late btw). The Grischuk - Nakamura game started off with a Berlin Defence to the Ruy Lopez (which is an opening known for a quick transition to an ending). On move 18 Grischuk decided that the king could be used as a fighting piece and moved it up the board. This was a brave decision as there were still plenty of pieces on the board (2R+3 minors each), and it was no surprise that found itself surrounded 10 moves later. However Grischuk had just enough the avoid getting mated and in the end Nakamrua had a repetition but no more.


Grischuk,Alexander - Nakamura,Hikaru [C67]
London Chess Classic Olympia, London (1.5), 04.12.2015