Chess game similarity measure?

[kinderchocolate]

I have a database of chess games in PGN format. My goal is to index them into a representation that I can search for similarity.

For example, let's say I have 2 games in King's Indian and 1 game in Queen's Gambit Declined. Now, I have a new Queen's Gambit Accepted chess PGN game. The closest in the database is the Queen's Gambit Declined game.

I'm thinking of converting the chess games into a vector space, but not sure exactly how to do it.

[Ferdy]

I have a database of chess games in PGN format. My goal is to index them into a representation that I can search for similarity.

For example, let's say I have 2 games in King's Indian and 1 game in Queen's Gambit Declined. Now, I have a new Queen's Gambit Accepted chess PGN game. The closest in the database is the Queen's Gambit Declined game.

I'm thinking of converting the chess games into a vector space, but not sure exactly how to do it.

For opening similarity, you can go for eco codes. There is material balance and pawn structure. Ending can be covered in material balance.