Since there isn't much information available about the Jibun Techo in English, and the sizes aren't the standards we use in the West, lots of people are wondering about the sizes of the Jibun Techos.
I only have the A5 Slim version of the Jibun Techo. There's also a B6 slim version. According to a Google Translate version of the official Kokuyo Jibun Techo page, the dimensions are as follows:
- A5 Slim Idea and Life books: 125 x 210mm
- A5 Slim 2017 Diary: 136 x 217mm
- B6 Slim (mini) Idea and Life books: 108 x 182mm
- B6 Slim (mini) 2017 Diary: 120 x 190mm
To give you a better idea of how big the A5 Slim version is, I took a bunch of photos comparing mine to other common notebooks and planners I have.
Hobonichi Cousin Avec 2016 (A5)
Hobonichi Weeks 2017
Traveler's Company Notebook Regular (Midori)
Traveler's Company Notebook Passport (Midori)
Roterfaden Taschenbegleiter (A5)
Inside Roterfaden Taschenbegleiter
Comparing pages to the Hobonichi Cousin Avec 2016
Comparing pages to Hobonichi Weeks 2017
If you want to find out more about the Jibun Techo, including more details on the mini (B6 slim) size, you can join the Jibun Techo group on Facebook.