コソ勉 is an educational app developed by StudyHacker Inc. for iPhone users. This free app is designed for individuals who want to study secretly and effectively. It is based on the popular article "The Coloring Study Method: How I Studied for 3000 Hours and Got Accepted into Kyoto University" from the study hacking media "STUDY HACKER". With コソ勉, you can implement the coloring study method on your smartphone without the need for any registration.

The app allows you to easily track your study time using a simple interface. You can color in grid squares to represent the time you spent studying. This visual representation helps you see your study time accumulation and the balance between different subjects at a glance. It also makes it easy to reflect on how you have been utilizing your time and boosts your motivation.

コソ勉 is incredibly user-friendly. You can assign different colors to subjects, create your own pens, and add or delete grid pages as needed. With just a single tap, you can check your total study time and the time spent on each subject.