Black has managed to exchange one pair of knights, but in the meantime White has regrouped and played f2 -f3 , which results in the immediate threat of e2-e4. Black now went wrong with . . .

. . . and Nielsen had no trouble converting his advantage.

Again we see two knights defending each other, tempting White to go for the ambitious and audacious . . .

Keeping all the minor pieces on the board. If White succeeds in driving the black pieces back from e4, his opponent will struggle with his pieces in a passive position.

Trying to immediately rid himself of his superfluous knight by force.

The unusually-placed rook on b4 still makes it difficult for Black to coordinate his pieces.

Now White was definitely better, though Black scraped a draw in the end.

Vacating the g8-square for the knight.

Of course, not to the active square f6 , when, after 16...Nf6 17.Nxf6+ Bxf6, White has tightened his grip on the dS-square as planned.