SUNSTAR Ukanmuri Clip & Mini – Is It Worth the Hype?
, by ZenPop Japan , 11 min reading time
If you’ve ever struggled to keep a book open hands-free, you’ve probably wished for a better tool like the SUNSTAR Ukanmuri Clip to replace heavy bookends or harsh metal clamps.
Launched a couple of years ago, the Ukanmuri Clip quickly became a stationery darling in Japan. It won the 2023 Japan Stationery Award (Grand Prize) and has been praised for its minimalist silicone design, silent operation, and the promise of holding books completely flat without damaging pages.
Sunstar even released adorable Sanrio collaboration versions (Hello Kitty, My Melody, etc.), which sent the cute-factor through the roof.
But awards and cute designs don’t mean much if it doesn’t work in real life. So the ZenPop team put both sizes through several weeks of daily use — and cross-checked our experience with hundreds of Japanese Amazon reviews (currently averaging 4.1–4.3 stars) — to give you the unfiltered truth.
Quick Specs Comparison - Ukanmuri Clip 2 VS Ukanmuri Clip mini
| Ukanmuri Clip (Standard) | Ukanmuri Clip mini | |
| Length | 12.2 cm | 7.2 cm |
| Weight | 33.1 g | 9.7 g |
| Material | Silicone-coated metal core | Silicone-coated metal core |
| Colors | 7 standard + Sanrio collabs | 7 standard + Sanrio collabs |
| Price (approx. on Amazon.jp) | ¥1,200–1,800 | ¥900–1,300 |
The Good – Why people love it
Zero damage to paper
Unlike traditional binder clips, the plastic is completely soft. Owners repeatedly say they leave it on art books and coated-paper catalogs for weeks with no marks.
Silent & kid-friendly
Parents and music teachers love this. One reviewer: “My elementary-school child uses it for kokugo and math textbooks every day — easy to handle and no annoying metal noise.”
Looks ridiculously good
Minimalist, premium feel. The Sanrio versions are a stationery flex.
Perfect for certain books
- School textbooks (especially soft-cover Japanese ones)
- Sheet music and thin scores (“exactly the right size for kids at piano lessons”)
- A5 softcover notebooks around 1.2–2 cm thick (Hobonichi Cousin, Stalogy, MD Notebook thick) When the thickness matches, it’s magical — the book lies completely flat.
The Not-So-Good – Real Limitations (Confirmed by Hundreds of Users)
The standard size is too tall for thin books
Same as we experienced: anything under ~1.4 cm creates an air gap and rocks when you write.
The mini is too weak for anything remotely thick
Multiple people tried it on game strategy guides, reference books, or magazines and reported the same thing: “It slips off when the left and right sides have different thicknesses.”
Biggest universal complaint: front-half / back-half problem
This is mentioned in almost every 1–3 star review:
“When you’re in the first 50 pages or the last 50 pages, one side is much thicker. The clip creates the same gap on both sides, so the thin side becomes loose and pages slowly flip.”
Several users directly compare it to X-shaped or crocodile clips and say those handle uneven thickness better.
Slippery paper makes it worse
Coated or glossy pages (common in catalogs, art books, and many strategy guides) reduce grip even more. One owner summed it up: “It seems made for sheet music or very thin books rather than 2 cm-thick strategy guides.”
Clamping depth is shallow
Even when you force the book open flat in the middle, many reviewers say the silicone “teeth” just don’t reach deep enough for stiff or glossy stock.
Side-by-Side Use Case Verdict
| Use Case | Standard Clip | Mini Clip | Winner / Real-User Vote |
| Thin A5 notebook (<1 cm) for journaling | ✘ Gap issue | ✓ | Mini |
| Thick A5 softcover (1.5–2 cm) | ✓ | ✘ | Standard |
| Japanese school textbook | ✓ | Sometimes | Standard |
| Sheet music / thin scores | ✓ | ✓✓ | Mini (kids love it) |
| Game strategy guide (>300 pages) | Sometimes | ✘ | Neither (slips) |
| Front or back of any thick book | ✘ Loose on thin side | ✘ | X-clip beats it |
| A4 catalog or magazine | ✘ | ✘ | Neither |
Who Should Buy Which One?
Get the standard Ukanmuri Clip if you mainly use:
Japanese school textbooks, Hobonichi Cousin / Stalogy / thick MD notebooks, or any soft-cover A5 book around 1.5–2 cm.
Get the Ukanmuri Clip mini if you mainly use:
Thin notebooks, sheet music, or kids’ textbooks. It’s the clear favorite among music students and elementary parents.
Skip both (or look elsewhere) if you need:
Something that reliably holds 300+ page reference books, glossy catalogs, or hardcovers all the way from page 1 to the end. Japanese users overwhelmingly say traditional X-clips or acrylic weights still win in those scenarios.
Final Thoughts – Beautiful, But Very Niche
The Ukanmuri Clips are some of the best-looking, most thoughtful book-holding tools out there. When your book falls into their sweet spot (school textbooks, sheet music, medium-thick A5 softcovers), they’re fantastic and live up to every bit of the hype.
But they’re not universal. The uneven-thickness problem that plagues the first and last sections of thicker books is real and mentioned in almost every critical review.
If your daily carry is a Hobonichi Cousin or a piano score → buy without hesitation (we still reach for ours constantly).
If you want one clip to rule magazines, strategy guides, textbooks, and notebooks → temper your expectations or keep a backup solution.
Measure your favorite book’s thickness, think about where you usually open it, and you’ll know instantly whether these little silicone beauties belong in your stationery rotation.
Ready to give them a try? Both the standard Ukanmuri Clip and the mini one are available now in the ZenPop online stationery store!
