user2698: Many videos on YouTube channel "Kingscrusher" which discuss the play of new neural-net engines like Leela Chess Zero focus considerable attention upon the development of "thorn pawns" which are pawns that have reached the sixth rank and are blocked by a pawn in front but do not have pawns ahead of them to either side.  In my limited study of the game in decades past, I've seen great significance given to passed pawns, but never any special attention given to thorn pawns.  Do such pawns have a significance that has only been fully brought out as a result of AI-assisted research, or have they always been understood but simply not in things I'd read?  Or is Kingscrusher giving them more significance than they deserve?
A typical thorn-pawn situation would occur when Black has pawns at f7, g7, and h7, white moves h5, Black g6, and white pushes h6.  If Black has castled kingside, that pawn at h6 can be very hard to capture, and its presence kills the escape square at g7 and the possibility of easily establishing one at h7.  Was that a common pattern in years past, and if so what was it called?

user12523: I had never heard the term, but such pawns are very important for their contribution to certain mating patterns, the most famous of which would be Damiano's mate, which was included in Damiano's 1512 book Questo libro e da imparare giocare a scachi et de li partiti. Here's an archetypal example:
[FEN "5rk1/6pQ/6P1/8/8/8/8/8 w - - 1 1"]


2698: <p>Many videos on YouTube channel "Kingscrusher" which discuss the play of new neural-net engines like Leela Chess Zero focus considerable attention upon the development of "thorn pawns" which are pawns that have reached the sixth rank and are blocked by a pawn in front but do not have pawns ahead of them to either side.  In my limited study of the game in decades past, I've seen great significance given to passed pawns, but never any special attention given to thorn pawns.  Do such pawns have a significance that has only been fully brought out as a result of AI-assisted research, or have they always been understood but simply not in things I'd read?  Or is Kingscrusher giving them more significance than they deserve?</p>

<p>A typical thorn-pawn situation would occur when Black has pawns at f7, g7, and h7, white moves h5, Black g6, and white pushes h6.  If Black has castled kingside, that pawn at h6 can be very hard to capture, and its presence kills the escape square at g7 and the possibility of easily establishing one at h7.  Was that a common pattern in years past, and if so what was it called?</p>
 12523: <p>I had never heard the term, but such pawns are very important for their contribution to certain mating patterns, the most famous of which would be <em>Damiano's mate</em>, which was included in Damiano's 1512 book <em>Questo libro e da imparare giocare a scachi et de li partiti</em>. Here's an archetypal example:</p>

<pre><code>[FEN "5rk1/6pQ/6P1/8/8/8/8/8 w - - 1 1"]
</code></pre>
