British Chess Magazine 28 (1908) notes "Our Hungarian contemporary, "Casopsis Ceskych Sachistu," announces the death of Jan Drtina and Jan Karel, two well-known Bohemian problem composers" (19).
That source confirms a his year of death as 1907 or 1908, both dates given in unsourced websites.
Anyone have any information concerning Jan Drtina?
Wikipedia identifies him as from Czechoslovakia. A few unsourced tidbits on the web credit him with discovering the concept of critical squares in pawn endings. I'd like a source.
Dvoretsky's Endgame Manual attributes to him this important study (solution is given at http://blog.chess.com/Ziryab/opposition-and-outflanking):