The Hobonichi Techo uses 12 soft colors across the book. The TSUKI no IRO stationery series incorporates these colors into simple designs.
These pens are a special collaboration made with Kakimori, a stationery shop that crafts fountain pens, inks, notebooks, and more, all created for “people who write with joy.”
Frost is an original Kakimori pen featuring a translucent body with the texture of frosted glass. It is thoughtfully designed so that even the faintly visible ink and nib become a part of the pen’s overall design.
The pen features an easy-to-open screw-on cap and a grip section made as long as possible to keep your fingers off the ridges while writing. Every detail has been refined to eliminate unnecessary elements, while still conveying a sense of both modernity and charm.
For this collaboration, we’ve kept all the beauty and ease of writing that Frost is known for, while giving the body a khaki gray color exclusive to the Hobonichi Techo, with the TSUKI no IRO logo added in silver. The translucent material means you can enjoy watching how the pen changes in appearance once it’s filled with ink.
Two nib types are available. The fountain pen offers a smooth, flowing writing experience, while the rollerball is a ballpoint-style option for everyday use. The fountain pen comes in an EF (extra-fine) nib width, perfect for writing small, detailed entries in your techo.
Both pens use a converter system, meaning you draw in ink yourself. We recommend pairing them with the TSUKI no IRO pigment ink or the mini ink bottle sets.

There’s more to the TSUKI no IRO stationery series. Enjoy exploring the world of all twelve colors. See the full lineup of the TSUKI no IRO series here.
How to fill with ink
Frost is a converter-style pen. Please fill it with ink before use.
Instructions for refilling:
- Fountain pen
- Rollerball pen
How to clean your pen
With proper, regular care, your pen will last for many years.
Cleaning instructions:
- Fountain pen
- Rollerball pen
How to use the cleaning solution
If ink has dried and hardened inside the nib, please use a cleaning solution.
Cleaning solution:
- Purchase here
- How to use
*Not available in the Hobonichi store.
Replacement nibs
The nib can be replaced. Whether your pen has stopped writing or you’d like to switch from a fountain pen nib to a rollerball, replacement nibs are available.
Replacement nibs:
- Fountain pen
- Rollerball pen
*Not available in the Hobonichi store.
(Replacement EF nibs will be available starting September 15, 2026.)
| Size | Length: 134 mm x Diameter: 14 mm / Length: 5.3" x Diameter: 0.6" |
|---|---|
| Weight | Approx. 14 g |
| Main material | Pen body: Polycarbonate / Pen nib: Stainless steel / Converter: Plastic |
If you’ve used any of these products, we welcome your notes on what you like about them or what led you to buy them so we can share it with customers who are currently considering these products. We’d also love to welcome comments from customers who purchased their techo outside the Hobonichi Store or received their book as a gift.
We’ve compiled a list of warnings, potential issues, and tips to keep in mind for this particular product. Additionally, the color of the product may be slightly different in actuality than compared to how it appeared on a computer or smartphone screen.
- Ink is not included.
- We recommend using pigment inks from Kakimori or Inkstand.
- Please write gently with the fountain pen without applying strong pressure to the nib.
- We recommend using the pen frequently (about once a day) to prevent the ink from drying out.
- If you will not be using the pen for an extended period, do not leave ink in the converter. Rinse the converter with water before storing it.
- Right after filling the pen with ink, the writing may appear lighter at first, but the color will naturally darken as days pass.
- Avoid storing the pen in environments with extremely low or high temperatures, or in direct sunlight.
- The cap is not designed to be posted on the back of the pen barrel while writing. Forcing it on may cause scratches.
- Ink stains inside the pen body may not be completely removable.
- Closing the cap with excessive force may cause the pen body to crack.
- When traveling by airplane, we recommend filling the pen after arriving at your destination, as changes in air pressure can cause ink to leak.
Even if it takes some time for the ink to reach the nib, please do not shake the pen strongly or push down on the converter. Doing so may cause ink to leak.






















