謎解きダイアリー 頭が良くなる脳トレ日記 is a free Android game developed by Jammsworks. The game consists of solving puzzles written in a diary format. Players are challenged to solve all the mysteries written in the diary for each month. Once all the puzzles for a month are solved, players can tap on the next month's sticky note to try out a rearrangement puzzle. Successfully solving the rearrangement puzzle unlocks the next month's mysteries. The game features a total of 90 puzzles, with increasing difficulty as the game progresses. Additional puzzles are planned to be added in future updates, with a maximum of 365 puzzles. Players receive a "keyword" for each puzzle they solve, which is needed for the rearrangement puzzles in the following month. The game also provides hints and a memo feature to assist players when they're stuck. For those who are still unable to solve a puzzle, there is a "view answer" button that reveals the solution. The game includes music from Music-Note.jp and Music is VFR, as well as sound effects from Pocket Sound. The icons used in the game are provided by icons8 and the materials are from ぴたちー素材館.