Pawn and Two: <Calli> 16...Nxd4 looks best for Black and maintains his advantage. However, Olland's 16...Bd6, also gives Black an edge.
In his book, "100 Instructive Games of Alekhine", F. Reinfeld states, <"Olland was afraid of opening up the game with 16...Nxd4, although one cannot see any direct risk in the capture">.
Fritz 9 evaluations after 16.gxh3:
16.gxh3 (-1.08)(16 ply) - if Nxd4 17.0-0-0 Bd6 18.Rhf1 Bxf4 19.Rxf4 c5 20.Nb5 Nxb5 21.Bxb5+ Kc7.
16.gxh3 (-.95)(16 ply) - if Bd6 17.Nb5 Ne4 18.Bxe4 Rf6 19.Nxd6 Qh4+ 20.Kd1 cxd6.
At move 21, Olland had the very strong move, 21...Kc7! available. After 21...Kc8?, White gets the advantage, as he will now get the threat 23.Ne7+.
If 21...Kc7!, Olland appears to have a winning position. Fritz 9 rates Black's position as winning (-1.98) (15 ply) and gives the following line:
21...Kc7! 22.Nf4 Qh8 23.Ne6+ Kb8 24.Qe3 Re8.
Fritz 9's evaluation is now (-2.40) (16 ply). If 25.0-0-0 Rxh3 26.Qf2 Rxe6.
Or (-2.43) (16 ply), if 25.Bf5 Ne7 26. 0-0-0 Nxf5.
Both players were on thin ice in this game.
Reinfeld said the following about this game: <To get the most pleasure out of games like this one, we must remember that both players want spirited chess, that a Pawn more or less is not the sum of existence to them. With Scott they believe that "one hour of life, crowded to the full with glorious action, filled with noble risks, is worth whole years of those mean observances of paltry decorum.">