Murder puzzles on paper. Every book starts easy and ends hard.
Gongoku · 100 murder puzzles on the floor plan
A country house, a gong that strikes every hour, and a murder you can reconstruct on the floor plan. One hundred puzzles across five houses, from 4×4 up to 8×8. Each chapter's killers spell out the poison.
Twelve floors and a secret thirteenth
A hotel full of murder puzzles of ten kinds. Every room yields a key that opens another room, and whoever cracks all twelve floors finds the lift to the thirteenth. 138 rooms, from easy to hard.
Murder puzzles in the snow
Fresh snow gives away who walked where. Follow the tracks and reconstruct the night.
One liar per case
Everyone gives an alibi. Only the killer lies. Lay the statements side by side until one no longer fits.