Jibun Techo (KOKUYO)

A Japanese planner built as three booklets that work as one: LIFE (things you keep for life), DIARY (this year, with a 24-hour weekly timeline) and IDEA (grid notes). Made by KOKUYO, designed by Hideaki Sakuma.

Correction to the brief. The brief named "Mitsuharu Sato, launched 2014?". Every source checked names the designer as Hideaki Sakuma (佐久間英彰). KOKUYO's first edition was the **2013 edition, on sale mid-September 2012**. 2014 is the year it won a Good Design Award.

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1. At a glance

2. Summary

Jibun Techo ("jibun" = myself, "techo" = pocket planner/notebook) is KOKUYO's "planner for a lifetime". Hideaki Sakuma built it for himself over about ten years because he worked ad-agency hours that ran past midnight and no planner showed the whole day. The result splits your records by how long they matter: the DIARY is replaced every year and centres on a weekly vertical spread with a 24-hour timeline, used both to plan and to log what really happened (a "lifelog"); LIFE holds things that last across years (life dreams, family tree, anniversaries, a personal timeline to age 99, contacts, medical and asset notes) and moves into each new cover; IDEA is a grid notebook for everything else. The lineup has grown to Biz (muted, business look, MIO paper), Lite (thin, simple) and DAYs (one page per day with a central timeline). For Journalwright Studio the most useful ideas are the full-day timeline with plan and actual side by side, the split between "this year" and "for life", season-shaded night hours, and a monthly project (Gantt) page.

3. History and origin

Who made it

Hideaki Sakuma worked as a creative director at a major Japanese advertising agency. KOKUYO's own product page credits him as the person who developed the original planner and notes it won a Good Design Award in 2014. KOKUYO's English blog and retailer interviews tell the same story: his days often ran late into the night and into the morning, and planners with an 8:00–22:00 timeline didn't fit. He designed pages for his own use, colleagues asked for copies, and it grew into a small independent product before KOKUYO took it on.

Some Japanese sources give his birth year and home prefecture; I could not open a primary source for those, so they are left out.

Timeline

Cultural context: Japanese techo culture

• Techo (手帳) means a small personal book for schedules, notes and records. Japan has a large, seasonal planner market: new editions arrive in August–September, many start in October or November, and stores run planner corners through year end.
• Corporate diaries used to be common gifts. After the early-1990s bubble burst many companies stopped printing and giving them, and the market turned toward personal, design-led planners bought by individuals (Japan Creative Enterprise, 2021). One count puts it at over 3,000 designs a year.
• Japan also has a very old diary tradition (Heian-period literary diaries), and a modern habit of "techo-jutsu" (planner techniques) books and magazine features. Jibun Techo is part of that planner-as-self-care wave, alongside Hobonichi Techo.

How it differs from Western planners

Key quotes

• KOKUYO series tagline (Japanese): 「ジブンのすべてが、この中に」 — "All of yourself is in here."
• KOKUYO release, 2016 and 2027 editions: 「一生つかえる」 — "Usable for a lifetime."
• KOKUYO store: "More than planning. It's discovering yourself."
• KOKUYO store blog: "A planner that changes every year. But don't you often wish to keep some information beyond the year?"
• Guidebook (Sakuma, 2025), paraphrased from the publisher page: handwritten records carry the "body temperature" of your real self, not a polished version.

4. Philosophy and principles

1. Your life doesn't end at 22:00. A planner should show the whole 24 hours so sleep, late shifts and early mornings are visible.
2. Plan, then record. The same timeline holds what you meant to do and what you did. Comparing them is the point.
3. Separate records by how long they matter. Yearly things go in DIARY. Lifetime things go in LIFE so you never recopy them. Loose thinking goes in IDEA.
4. Take the guesswork out of what to write. KOKUYO's page stresses carefully designed formats so you never face a blank page wondering what to put.
5. Easy to write, easy to read, easy to find (Itoya event page). Tidy grids, clear headings, index stickers.
6. Self-discovery through records. The "jibun" in the name: logging your days reveals patterns in who you are.

Problem it solves: schedules that ignore real hours, and life records scattered across years of old diaries.

5. Core components

5.1 Annual schedule

A year of rows. Most people mark trips, deadlines, birthdays and the start and end of big stretches (a new job, a course). It's the page you check when someone asks "are you free in June?".

5.2 Monthly block

A standard grid month. Sources describe soft colours that change each month in the Standard edition, and a Biz version in muted tones. The 2016 edition added the previous month's closing dates so you can see across the break.

5.3 Monthly project (Gantt)

A table of rows by days. Uses: project bars, habit tracking (fill a cell per day), a period or symptom tracker, or counting hours of something. Lite mini (2020 edition, out 2019) put the Gantt and the month calendar on the same page.

5.4 Weekly vertical 24-hour

The heart of the system. Seven day columns across a two-page spread, a vertical time axis from 0:00, divided into half-hour steps (PC Asobu). Night hours are shaded; Waki Bungu notes the shading shifts by season to show dark hours (sunrise near 5:30 in April, near 7:00 in December in Tokyo). Most users split each day column in two: **left = plan, right = actual** (PC Asobu). Space at the foot of each day holds notes; Galen Leather's review mentions room for mood and weather.

5.5 Yearly lists

"100 things to do this year", favourite quotes, books and films, gift log, a promise list (things you told someone you'd do). These keep small facts out of the weekly pages.

5.6 Year review

A structured look back: highlights, what went well, what happened, what didn't.

5.7 LIFE booklet

Moves from cover to cover each year. KOKUYO frames the LIFE + IDEA pair as what makes it a lifelong planner rather than a disposable annual one. Sections vary by edition; the 2013 edition listed 11, later ones add medical history, more maps and "The Years" pages running from birth to age 99 split into personal, family and world columns.

Privacy note. LIFE includes a password list. Anyone who adopts this idea should store hints only, never full passwords, and never carry it daily. Journalwright Studio's Keeper (a home-kept companion book) already does this.

5.8 IDEA booklet

A grid notebook, sold separately in packs, for anything: meeting notes, brainstorms, recipes, sketches, journaling. It lets the DIARY stay clean.

5.9 Lifelog

Logging what you actually did, in time blocks, after the fact. Over weeks you see sleep patterns, how much time goes to commuting or screens, when energy dips. The DAYs edition extends this to a whole page per day with a central timeline and room on each side (for example "to-do and schedule" on one side and "work and personal log" on the other, per KOKUYO's DAYs mini page).

5.10 Colour coding

Not an official fixed system; KOKUYO sells template stickers and the sample pages suggest colours. Waki Bungu's writer followed the sample: yellow for personal time, blue for work. Common community sets add green for exercise or outdoors, pink or red for social, grey for sleep. Keep it to 3–5 colours.

6. Setting it up

First setup (30–60 minutes)

1. Pick a size. A5 slim if you write big or log a lot; B6 slim to carry.
2. Pick an edition. Standard First Kit for the full LIFE/DIARY/IDEA system; DAYs if you want a page a day; Lite if you only want a slim weekly log; Biz for a plain look.
3. Put LIFE and IDEA in the cover alongside DIARY (First Kit comes this way).
4. Choose 3–5 colours and write the key on the inside cover or first page.
5. Fill the annual schedule with fixed dates you already know.
6. In LIFE, fill anniversaries and contacts first. Leave the big pages (dreams, The Years) for a quiet afternoon.
7. Add index stickers to each month.
8. Decide your split in each day column: plan left, actual right.

The first day

• Morning or night before: write fixed plans in the left half (shift, appointments, bus).
• During the day: nothing, or quick ticks.
• Evening (3–5 min): draw lines in the right half for what actually happened. Colour them. Shade sleep.
• One line of notes at the bottom: mood, weather, one good thing.

The first week

• Days 1–3: just log. Don't judge.
• Day 4: add a habit row or two on the monthly project page.
• Day 7: look at the spread. Where did sleep, work and rest land? Write one sentence about what you noticed.

7. Daily practice

Prompts for the note line: What took more time than planned? When did I have the most energy? What would I move tomorrow? One thing I want to remember?

8. Rhythms

• Weekly (10–20 min): fill next week's plan halves; look at last week's actuals; move unfinished tasks; count hours in each colour if you like.
• Monthly (20 min): update the monthly block; add a line to the monthly project; fill the lists (books read, gifts); copy any lifetime facts into LIFE (new anniversaries, a place visited on the map).
• Quarterly: check the "100 things this year" list; tick or drop items.
• Yearly: fill the year review; add a line to LIFE's "The Years" for this year (personal, family, world); move LIFE and the current IDEA into the new cover; archive the old DIARY with the year on the spine.
• Migration: there is none in the Bullet Journal sense. Lifetime info goes to LIFE once; the DIARY is archived.

9. Page anatomy

Proportions: A5 slim is 217 × 136 mm, about 1.6:1 (tall and narrow). B6 slim is 190 × 120 mm. Weekly and monthly pages use a fine grid ruling behind the formats (IDEA is plain grid). Exact grid pitch not confirmed; retailers describe roughly 3.5–4 mm (uncertain).

9.1 Weekly vertical 24-hour (two-page spread)

 LEFT PAGE                                    RIGHT PAGE
+--------------------------------------+   +------------------------------------------+
| WEEK 41   OCT 2026          [mini cal]|  |                               [mini cal] |
+----+--------+--------+--------+-------+  +--------+--------+--------+--------+------+
|    | MON 5  | TUE 6  | WED 7  |       |  | THU 8  | FRI 9  | SAT 10 | SUN 11 | memo |
|    | pl |ac | pl |ac | pl |ac |       |  | pl |ac | pl |ac | pl |ac | pl |ac |      |
+----+----+---+----+---+----+---+       |  +----+---+----+---+----+---+----+---+      |
| 0  |////|///|////|///|////|///|       |  |////|///|////|///|////|///|////|///|      |
| 2  |////|///|////|///|////|///|  shaded  |////|///|////|///|////|///|////|///|      |
| 4  |////|///|////|///|////|///|  night   |////|///|////|///|////|///|////|///|      |
| 6  |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 8  |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 10 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 12 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 14 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 16 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 18 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 20 |    |   |    |   |    |   |       |  |    |   |    |   |    |   |    |   |      |
| 22 |////|///|////|///|////|///|       |  |////|///|////|///|////|///|////|///|      |
+----+--------+--------+--------+       |  +--------+--------+--------+--------+      |
|note| ...... | ...... | ...... |       |  | ...... | ...... | ...... | ...... |      |
+----+--------+--------+--------+-------+  +--------+--------+--------+--------+------+
 Axis: 0:00 to 24:00 in half-hour rows. pl = plan, ac = actual (user's own split).

Where things sit: time axis far left; day columns equal width; notes band at foot; small month calendars top corners.

9.2 Monthly block

+--------------------------------------------------------------+
| OCTOBER 2026                                  goals: ....... |
+--------+--------+--------+--------+--------+--------+--------+
|  MON   |  TUE   |  WED   |  THU   |  FRI   |  SAT   |  SUN   |
+--------+--------+--------+--------+--------+--------+--------+
| (28)   | (29)   | (30)   |   1    |   2    |   3    |   4    |
|        |        |        |        |        |        |        |
+--------+--------+--------+--------+--------+--------+--------+
|   5    |   6    | ...                                         |
+--------+--------+--------------------------------------------+
 (28)(29)(30) = previous month's end dates in grey (2016 edition onward)

9.3 Monthly project (Gantt)

+----------------+--+--+--+--+--+--+--+--+--+--+--+--+ ... +--+
| PROJECT/HABIT  | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|     |31|
+----------------+--+--+--+--+--+--+--+--+--+--+--+--+ ... +--+
| Meds           |##|##|##|##|  |##|##|##|##|##|##|##|     |  |
| Walk 20 min    |##|  |##|  |  |##|##|  |##|  |  |##|     |  |
| Move apartment |  |  |  |  |==|==|==|==|==|==|  |  |     |  |
+----------------+--+--+--+--+--+--+--+--+--+--+--+--+ ... +--+

9.4 LIFE: The Years (birth to 99)

+-----+------+----------------------+----------------------+--------------------+
| YR  | AGE  | ME                   | FAMILY               | WORLD              |
+-----+------+----------------------+----------------------+--------------------+
| ... | ...  |                      |                      |                    |
| 2026| 34   | moved to a new city   | sister's baby born   | ...                |
+-----+------+----------------------+----------------------+--------------------+

9.5 LIFE: Anniversaries (365 days)

+------+---------------------+------+---------------------+
| JAN  |                     | FEB  |                     |
|  1   |                     |  1   |                     |
|  2   | Mom's birthday      |  2   |                     |
|  ... |                     |  ... |                     |
+------+---------------------+------+---------------------+

9.6 DAYs daily page (one page per day)

+-------------------------------------------+
| TUE 6 OCT 2026                  weather   |
+-------------------+---+-------------------+
| TO-DO / SCHEDULE  | 0 | LOG               |
|                   | 2 |                   |
|                   | 4 |                   |
|                   | 6 |                   |
|                   | 8 |                   |
|                   |10 |                   |
|                   |12 |                   |
|                   |14 |                   |
|                   |16 |                   |
|                   |18 |                   |
|                   |20 |                   |
|                   |22 |                   |
+-------------------+---+-------------------+
|  free space                               |
+-------------------------------------------+
 A "T" shape: date bar across the top, timeline down the middle.

9.7 IDEA page

Plain grid, edge to edge, with a small date/title line.

10. Worked examples

A sample day (actual half of a Tuesday, shift worker)

 TUE 6 OCT      plan            | actual
 0:00-6:00      sleep           | sleep (woke 3:10, back 3:40)       [grey]
 6:30           bus 6:48 rt 33  | bus 6:48                           [blue]
 7:30-15:30     shift (outdoor) | shift, rain after 11               [blue]
 16:00          pharmacy        | pharmacy, pickup done              [yellow]
 17:00-18:00    rest            | nap 17:10-17:50                    [grey]
 18:30          dinner w/ J     | dinner w/ J, laughed a lot         [pink]
 20:00-21:00    sketch          | scrolled phone 20:00-20:50         [none]
 22:30          sleep           | sleep 23:15                        [grey]
 note: tired but okay. Mood 3/5. Rain. Good: J's story about the cat.

A sample week (summary line under Sunday)

 Sleep avg ~6h40 (Tue short, Sat long)   Work 38h   Walk 3x   Meds 7/7
 Noticed: evenings I plan to sketch become phone time. Try: sketch right after dinner.

A sample month (monthly project page, October)

 PROJECT/HABIT  1 2 3 4 5 6 7 8 9 ...
 Meds           # # # # # # # # # ...
 Walk           #   #     # #   # ...
 Estradiol inj  #             #   ... (weekly)
 Find new GP    = = = = = = =        (bar = working on it; done 7th)
 Month note: fewer late nights than September. Two bad sleep weeks followed double shifts.

11. Variations and offshoots

12. Community practice

What people actually do (from reviews and blogs; anecdotal):

• Plan left, log right on each day column is near-universal.
• Highlighter bars for the actual log, so the week becomes a colour chart of your time.
• Sleep shading and counting sleep hours per week.
• Monthly project page as habit tracker rather than for projects.
• Covers: the A5 slim fits some Hobonichi-size folios; the B6 slim fits some traveler's-notebook-style wallet inserts (Galen Leather review).
• Decoration camp: stickers, washi tape, Japanese stamp sets, template stickers from KOKUYO.
• Minimal camp: one black pen, one or two colours, lines only.
• Many users ignore parts of LIFE (40-year family plan, rail maps) and fill only anniversaries, dreams and The Years.

13. Official products and formats

• Japan prices (2027): ¥3,000–¥5,600 before tax for notebooks; accessories ¥640–¥980. DAYs mini SOU·SOU (2026) ¥4,000 before tax, 216 sheets.
• Paper: THIN PAPER (Standard, DAYs, Lite): light, bright white, resists ghosting and wrinkling from erasers. MIO PAPER (Biz): thicker, smooth, fast-drying, liked by fountain pen users. Earlier editions (2016) used Tomoe River for DIARY/IDEA.
• Binding: sewn booklets with flexible covers that slide into a clear cover.
• Release cycle: announced early August, on sale mid-September; the DIARY starts in November, DAYs in January.
• Where sold: Loft, Itoya, Tokyu Hands and other Japanese stationers; kokuyostore.com; JetPens and similar importers.
• Accessories: clear covers, under-mats (shitajiki), month index stickers, template stickers (plan and icon versions), zipper cases, replacement booklets.

14. Tools and supplies

• Pens: fine gel pens (0.3–0.4 mm) suit the tight grid; erasable pens work on THIN PAPER. Fountain pens: MIO PAPER (Biz) is better; THIN PAPER shows some ghosting, as all thin paper does.
• Highlighters: mild or pastel ones for the lifelog bars (less show-through).
• Paper weight: thin (Tomoe-River-like). Expect ghosting, not bleed, with most gel inks.
• Rulers: a 15 cm ruler or the included card ruler for clean bars.
• Stickers and stamps: KOKUYO template stickers; small icon stamps for sleep, meds, weather.
• Under-mat: helps with thin paper so you don't emboss the next page.

15. Digital and hybrid versions

• Apps: any calendar with a 24-hour week view (Google Calendar week view shows 24h), time trackers (Toggl, ATracker, aTimeLogger) that draw colour bars. A GoodNotes/Notability PDF planner with a 24-hour vertical week gives the same layout; many are sold on Etsy.
• E-ink: reMarkable, Kindle Scribe and Boox can load 24-hour weekly PDF templates with hyperlinks. Colour coding is lost on mono screens; use patterns (solid, hatched, dotted) instead.
• Scanning: the weekly spread scans well; colour bars need a colour scan to be read later.
• Lost vs paper: tactile writing, the at-a-glance colour chart of a week, and the LIFE booklet's long life.
• Gained digitally: automatic totals of hours per category, search, backups.

16. Evidence and research

No studies test Jibun Techo itself. Two strong adjacent findings:

Claimed vs supported:

• "Seeing your time helps you manage it": plausible and partly supported (monitoring research), untested for this book.
• "Writing by hand reveals who you are": claimed, not tested.
• "Lifelong records improve life satisfaction": claimed, not tested.

17. Benefits

• Makes hours visible, including sleep and late nights (claimed; logic of time-use diaries).
• Monitoring habits on paper helps goal progress (evidenced, adjacent: Harkin 2016).
• Accurate record of how the day went, from episode-by-episode recall (evidenced as a method: Kahneman 2004).
• Fits shift work and night owls, since the day doesn't stop at 22:00 (claimed).
• No recopying of lifetime info each year (claimed).
• Structure reduces "what do I write?" (claimed).
• A year of colour bars is motivating to look back on (claimed).

18. Pitfalls

19. Accessibility and adaptations

• ADHD: the timeline shows time passing, which helps time blindness. Log after the fact rather than plan every slot. Use one highlighter per "type of energy", not per task. Don't back-fill missed days.
• Autism and sensory needs: the fixed structure suits people who like predictability. Choose Biz or Lite for calmer colours. Track sensory load as a bar colour or a row on the monthly page.
• Chronic illness and low spoons: log rest and symptoms as bars; the full-day view shows crash patterns after busy days. Use the Gantt page for symptoms and meds. On bad days, one word in the notes counts.
• Depression and anxiety: logging actual activity can support behavioural activation (seeing small actions). But a page of empty hours can sting; log only what you did, never what you didn't.
• Trauma: the LIFE "The Years" and family tree pages can bring up hard memories. Skip them; nothing breaks.
• Dyslexia and dysgraphia: use bars, icons and colours instead of words; the timeline carries meaning without text.
• Low vision: the slim grid is small. Print a larger home-made 24-hour week, or use a 24-hour digital view with zoom.
• Motor or hand pain: use A5 slim, thick pens, stickers or stamps for common activities.
• Trans and gender-diverse people: use The Years to record your own milestones (name, transition steps) in your own words; the monthly Gantt page tracks HRT schedules well. Keep LIFE private if the family tree uses dead names.
• Shift workers: the strongest fit of any mainstream planner, because the whole 24 hours is printed. Shade shifts; night shifts don't fall off the page.
• Low income: the book is costly outside Japan. A printed 24-hour week on plain paper or a free PDF does the same job; IDEA can be any grid notebook.

20. Comparison

21. Combining

• With a Bullet Journal: use the Jibun weekly timeline as the log, and BuJo bullets and collections in IDEA. See bullet-journal.md.
• With Hobonichi: Jibun for time and schedule, Hobonichi for daily writing. See hobonichi-techo.md.
• With a Traveler's Notebook: the B6 slim DIARY can live in a B6 elastic cover with IDEA and other inserts. See travelers-notebook.md.
• With time blocking: Jibun's plan half is time blocking; the actual half adds the review. See time-blocking.md.
• With habit or mood trackers: the monthly project page is a ready habit grid. See habit-tracking.md.

(Sibling docs are being written in parallel; these paths assume their planned names in docs/journaling/methods/ and may need a fix once they land.)

22. Ready-to-use bank

Timeline categories (pick 3–5):

1. Sleep
2. Work or shift
3. Care (meds, meals, hygiene)
4. Rest (not screens)
5. Screens
6. Moving or outside
7. People
8. Travel and bus
9. Making (art, writing)
10. Chores

Daily note prompts:

1. What took longer than I thought?
2. When did I feel most like myself?
3. What drained me? What refilled me?
4. One thing to move tomorrow.
5. Mood 1–5, energy 1–5.

Monthly project rows:

1. Meds taken
2. Water
3. Walk or outside time
4. Dated dose (for example an injection or patch)
5. Bedtime before midnight
6. Pain level (0–3 as dots)

Yearly lists (DIARY-style):

1. 100 small things to do this year
2. Books and films
3. Promises I made (to whom, by when)
4. Gifts given and received
5. Places I went

LIFE pages for the Keeper (the home-kept companion book):

1. Anniversaries by date
2. The Years: me, people, world
3. Places map (colour in)
4. Life wishes (no deadlines)

23. Glossary

24. FAQ

1. Is it one book or three? Three thin booklets in one cover: LIFE, DIARY, IDEA. You can buy DIARY alone.
2. Who invented it? Hideaki Sakuma, an ad-agency creative director. KOKUYO has made it since the 2013 edition.
3. Does it start in January? The Standard DIARY starts in November; DAYs starts in January; Biz and Lite start around December or January depending on edition year.
4. Is the paper fountain-pen friendly? Biz (MIO PAPER) is best. THIN PAPER in the others is light and resists bleed but shows ghosting.
5. Is it available in English? The layout is mostly numbers and icons; headings are in English and Japanese. Holidays and rail maps are Japanese.
6. Do I need to fill every half hour? No. Most people log transitions or only a few categories.
7. What's the difference between DAYs and Hobonichi? DAYs is built round a central 24-hour timeline; Hobonichi's daily page is mostly open grid for writing.
8. Can I reuse LIFE? Yes. That's the point: move it to next year's cover.
9. Is it good for shift workers? Yes. It is one of the few planners with the full 24 hours printed.
10. Is it safe to keep passwords in LIFE? Don't. Keep hints only, at home.

25. For Journalwright Studio

Journalwright Studio makes printed journals and planners designed in a block editor, with an optional e-ink companion (the X4 companion). This section turns the research above into day page blocks, X4 items and a method layout.

a. Printed book

b. X4 companion

c. Editor blocks

d. Proposed method layout ("Jibun day")

This layout is not among the built-in method layouts yet (today: original, Bullet Journal daily, Hobonichi, Five Minute, Theme System).

1. Moon/sun/season (for sunrise and sunset)
2. Events
3. Time line 24 h (tl24: plan + actual, start 0, shade night on)
4. Top priorities (3)
5. fields "Hours today": Sleep, Work, Rest, Out
6. Care check-in
7. Lined notes (3 lines: "note / mood / weather")
8. Tomorrow's first step (Lined notes preset)

e. Don't adopt

• Password list. Never in a carried or scanned book. The Keeper keeps hints only.
• Colour as the only signal. The books are black and white; use patterns and icons.
• Half-hour logging as a daily expectation. Too much for low-energy days; make actual logging optional.
• Rail maps, 40-year family plan, asset pages. Not relevant or too heavy for a calm book.
• Scores or totals that feel like grades on the X4 (hours "productive" etc.). Stay descriptive.

26. Open questions

• Exact first-release year of Biz and Biz mini (sources only in search summaries).
• Whether DAYs started with the 2020 or 2021 edition (sources disagree; likely the 2021 edition sold in 2020).
• The exact grid pitch and the time range printed (sources say 0:00–23:30 half-hour rows; some retailers may differ by edition).
• Whether the 2011 test sale of a 2012 edition happened as described.
• Whether seasonal sunrise shading is in every edition or only some.
• Biz start month (the US store says December, kokuyo.com says January).

27. Further reading

• Jibun Techo Official Perfect Guidebook (Hideaki Sakuma, Jitsumu Kyoiku, 2025): user examples and format guide from the designer (Japanese).
• KOKUYO store blog "What Is Jibun Techo?": official English overview of every edition.
• Galen Leather, "A Review of the Jibun Techo Japanese Planner System": a user's walk-through of all three booklets.
• Waki Bungu, "今さら聞けない人気手帳「ジブン手帳」": a Japanese stationer's page-by-page look, with colour-code example.
• Japan Creative Enterprise, "The Techo Culture & Evolution in Japan": short history of Japanese planner culture.
• Kahneman et al. (2004): why reconstructing a day by episodes works.

28. Sources

All checked 28 September 2026.

1. KOKUYO, "ジブン手帳｜文具｜コクヨ" (series page), https://www.kokuyo.com/stationery/series/jibun-techo/
2. KOKUYO, "一生つかえる手帳、「ジブン手帳」2027年版を発売" (release, 7 Aug 2026), https://www.kokuyo.com/news/release/260807st2/
3. KOKUYO, "「ジブン手帳」2016年版シリーズを発売" (release, 29 Jul 2015), https://www.kokuyo.com/news/release/150729st3/
4. KOKUYO, "新開発のオリジナル原紙を採用した「ジブン手帳」2020年版を発売" (release, 8 Jul 2019), https://www.kokuyo.com/news/release/20190708/
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6. KOKUYO, "Jibun Techo DAYs mini 2026 Limited Edition SOU・SOU Blue", https://www.kokuyo.com/en/stationery/category/diary/diary/18488/
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8. KOKUYO Official Store, "What Is Jibun Techo? A Complete Guide to KOKUYO's Journal Planner", https://www.kokuyostore.com/en_US/blog/blog44-what-is-jibun-techo.html
9. Newsfront, "コクヨ、"ライフログ"をつける「ジブン手帳」2013年版を発売、3990円" (5 Jul 2012), https://www.newsfront.jp/nifty-business/7995/
10. Nichima, "10年かけて個人で制作しネットで話題の「ジブン手帳」 コクヨS&Tから", https://www.nichima.co.jp/new_item/entry/821.html
11. ITmedia, "“インディーズ手帳”だった「ジブン手帳」をコクヨが発売するようになったわけ" (10 Aug 2012; page text partly garbled when read, used only for the 2010 start), https://www.itmedia.co.jp/bizid/articles/1208/10/news012.html
12. Itoya, "G.Itoya4階 KOKUYO・ジブン手帳開発者 佐久間英彰氏来店 10月5日(土)" (2019), https://www.ito-ya.co.jp/ext/store/itoya/gitoya/recommend/2019/09/003733.html
13. Jitsumu Kyoiku Shuppan, "ジブン手帳公式 パーフェクトガイドブック" (Hideaki Sakuma, 2025), https://books.jitsumu.co.jp/book/b659803.html
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16. Katy Klassman, Galen Leather, "A Review of the Jibun Techo Japanese Planner System", https://www.galenleather.com/blogs/news/jibun-techo-japanese-planner-system
17. Michelle Lim, Japan Creative Enterprise, "Japanese Stationery: The Techo Culture & Evolution in Japan" (26 Nov 2021), https://jbr.japancreativeenterprise.jp/2021/11/26/japanese-stationery-the-techo-culture-evolution-in-japan/
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