Here are some more examples of Leela demonstrating this same concept:
You're White, playing as Leela. Black's knight has invaded your 4th rank! What to move?
You're playing Black, as Leela. White's knight has just invaded your fourth rank. What do you play?
You're Leela, playing as Black. White has just placed a knight on your fourth rank. What do you play?
You're Leela, playing as White. Black has planted a knight on your fourth rank. What do you play?
If you've seen enough games by the self-taught engine Leela ("Lc0"), you might've noticed an interesting preference of hers, one that I call the "4th-Rank Eviction".
I call it this because Leela seems to strongly dislike whenever one of her opponent's pieces has invaded her fourth rank. Especially in the early phases of the game. She'll almost always (without fail) take action to evict the intruding piece, as soon as it's safely possible.
Example:
You can find this in game after game of "hers": if a piece invades her fourth rank, she'll almost always try to kick it away.
Notice that this is slightly different than the more common approach that many beginners take: they place a pawn on h3/h6 (or a3/a6), before a bishop or knight lands on the g4/g5 (or b4/b5) square. Like so:
Beginner players often do this as a preventative measure, because they don't want to get pinned. Or because they want to create an "escape square" to prevent back-rank mates. Or any number of other reasons.
Leela, though, will usually allow a piece to invade the 4th rank first. Then she will "put the question to it", usually with a pawn jab. The opponent then has to either retreat the piece, or exchange it away. In either case, Leela accomplishes her goal of evicting the piece from her 4th rank.
This might seem like a minor thing, (and certainly nothing new to experienced players), but it's a pretty consistent approach by Leela.
I've adopted it into my opening repertoire and found (unsurprisingly) that doing so always aligns with Grandmaster move preferences.
For example, in the Queen's Gambit Declined:
Here, playing pawn to ...h6 is an example of Leela's "4th-rank eviction" idea. Just by following that idea, Black has automatically found the "best" move.
Also interesting to note: below the 2200 level, the human preference here is to castle (...0-0), rather than playing ...h6.
At the master level, though, ...h6 becomes the preferred move. And we already know that it's the preferred approach of Leela, as well.
(You can also extend the idea to any knights or bishops that may try to occupy an outpost on the c/d/e/f files. If the intruding piece enters the fourth-rank, there's a good chance Leela would take action to try to evict it, as soon as possible.)
If you aren't already doing this in your games, consider trying it out. Or toy around with it, in your home analyses. See what you can learn from it.
What do you think of this concept?
Happy chessing!