Kasparyan's zettelkasten consists of 24 wooden boxes and at least two plastic trays of cards. The trays are numbered and the highest numbered tray has the number 34 on it.

In the picture are two plastic trays, but it's not obvious how big they are or how many cards they may contain.

Approximating that these would contain about 1,200 cards each, the collection is likely between 28,800 and 40,800 cards.

✅ https://t.co/5nGvHBm5Vo<br>Today I made a video about Henrik Kasparian's chess puzzle database which includes 30 thousand chess puzzles! In the precomputer era Kasparian used index cards to select everything in one place, and it took him decades to complete!#chess #chesspuzzle pic.twitter.com/V1H2PMKfjN

— Suren (@surenaghabek) August 3, 2020

via ARVES Chess Endgamestudy Association at https://arves.org/arves/index.php/en/endgamestudies/studies-by-composer/90-genrikh-kasparyan

Presumably Genrikh Kasparyan used his card index of chess puzzles as material to write one of his many books including: - Domination in 2,545 Endgame Studies by Genrikh Kasparyan. ISBN 0-923891-87-0 - 888 Miniature Studies by Genrikh Moiseyevich Kasparian. ISBN 978-86-7686-147-7

As a chess champion, he surely used to to fuel his chess studies and chess career.

It Took Decades To Create This Chess Puzzle Database (30 Thousand), 2020. https://www.youtube.com/watch?v=Y9craX0M_2A.

A chess School named after Genrikh Kasparyan (alternately Henrik Kasparian) houses his card index of chess puzzles with over 30,000 cards.

The cards are stored in stacked wooden trays in a two door cabinet with 4 shelves.

There are at least 23 small wooden trays of cards pictured in the video, though there are possibly many more. (Possibly as many as about 35 based on the layout of the cabinet and those easily visible.)

Kasparyan's son Sergei donated the card index to the chess school.

Each index card in the collection, filed in portrait orientation, begins with the name of the puzzle composer, lists its first publication, has a chess board diagram with the pieces arranges, and beneath that the solution of the puzzle. The cards are arranged alphabetically by the name of the puzzle composer.

The individual puzzle diagrams appear to have been done with a stamp of the board done in light blue ink with darker blue (or purple?) and red inked stamped pieces arranged on top of it.

ᔥu/ManuelRodriguez331 in r/Zettelkasten - Chess players are memorizing games with index cards