THIS IS JUST FOR FUN. DO NOT TAKE ME SERIOUSLY. I’M JUST FOOLING AROUND.
Another TRP comparison online article?
The purpose of this article is primarily for my benefit (I’m just having fun). As you all know, I was a PhD student. So, research is my jam. I also read a bit of the Tomoe River Paper articles from enthusiasts and users (like me). Their articles are mostly in the perspective of how-well-will-my-fountain-pen-write-on-this and will-it-bleed-through. If you’re looking for answers to those questions (with pictures), this is not the article for you.
Instead, we want to understand the mysterious processes of that makes Tomoe River Paper (TRP) special using various unverified resources and a little bit of deduction. Again, none of what I say is verified. Do not quote me.
Love for TRP
Don’t get me wrong. I will ALWAYS love TRP. According to Galen Leather, TRP is the best paper for fountain pens. TRP is designed to prevent bleed-throughs while remaining very thin (52 g/m2). It’s a secret how the Shizuoka Plant’s machine #7, and then, #9 produced such thin papers that could hold ink so well.
TRP was originally designed in 1980s as catalogue papers (for ads in your mail). There’s also some sources that say it was primarily used in Bibles. It did a good run and even better run when it was discovered that TRP worked well in notebooks for fountain pen users. The fountain pen ink does not bleed through. And, the paper is so light that it was great as a planner book. You have a light book that could have the entire year.
The downside is that the paper is so thin and porous. With use, the planner becomes heavier and the paper becomes curled. The earlier versions of the paper in the Hobonichi (circa 2017-8 and earlier) did not have the good coating we now enjoy. The coating (discussed below) easily fell apart and offered no added support. This means if you put washi down, you can’t pull it back up without peeling the paper or tearing the paper. I think the better coating came in 2019. At least, by 2020, it had achieved the best coating it could have. The fountain-pen-ink performance did not vary significantly throughout. It was only later when there had been reviews of the fragility of the paper that changes were made.
What’s in a Tomoe River Paper?
Tomoe River paper is primarily composed of wood pulp that is sandwiched between a layer of coating (source: Galen Leather). Wood pulp (henceforth, base paper) is shredded and moulded into thin sheets. Then, a clay-based coating is applied. This coating gives the paper luster, smoothness, and maybe added opacity. The wet coated paper is run through rollers to polish the coating. It is then dried and cut. Because TRP is super-thin, the rest of the process (packaging etc) is done by hand.
Clay coating is usually heavier than the base paper, adding as much as half of the g/m2. Remember this, we will get back to this later. Not only is coating heavy, it is also very expensive. It appears that the coating process is very special to each machine (includes base paper preparation) and could be proprietary (IP). Premium coating, however, could give a luxury feel (smooth texture and gloss). We do not know if Tomoegawa Paper (makers of TRP) used premium or lower level coating. As I mentioned, there was a change in coating around the time that production shifted from #7 to #9.
What makes TRP special?
In my opinion, TRP is special because of how it handles (no bleed-through) ink while being quite thin at the same time. This actually defies logic. Usually, thin papers have a lot of bleed-through but TRP doesn’t behave in that way. Reduced paper thickness allows the book to be lighter and more compact, this is why Hobonichi Weeks is originally so compact. However, thin papers uses less pulp. So, how does this work?
The true genius of TRP lies in the process of putting together the paper. We don’t know how this really happens… even Sanzen Paper (new TRSP paper manufacturers) were not successful in getting the formula from Tomoegawa Paper. But the interview by Hobonichi with Sanzen offered some bread crumbs. Sanzen says that TRP base paper has microscopic gaps. When the base paper is pressed, there will be gaps left within the material. Somehow, TRP found a way to hold the ink on the outer surface of the paper. The way to do this is to have varying sizes of gaps, with smaller gaps in the interior of the base paper. The bigger gaps on the surface/exterior take the ink from your fountain pen. But this ink stays on that side since the smaller gaps under the big gaps won’t let the ink through to the other side. The gaps of the inorganic coating could be more inform and less chaotic than the organic base paper. It is also possible that the gaps are smaller but more numerous. This could allow more controlled ink deposition resulting in minimal feathering (or only microscopic feathering).
This is the logic behind thicker papers. Because the thicker papers have many layers, the ink can’t go through all the layers to get to the other side (bleed-through). But what about thin papers? The clay coating could help with this. The coating itself is a layer. I suspect that the coating layer is significant enough to hold ink at the surface. It could also explain why water-based ink takes forever to dry. Water-based ink is not just water. The ink has pigments that may be too bonded to flow inside the gaps quickly. This is definitely why I suspect that oil-based ink smudges. Oil particles are bonded well and would not readily sink into the gaps. With heat through contact, oil-based particles are dislodged from gaps.
The end of Tomoe River Paper
Tomoegawa Paper is 100 years strong. Unfortunately, this does not mean financial stability. A few years back, wood pulp went on a steady rise. Tomoegawa Paper was wise enough to cut their loses before their century-old company sinks. In order to do so, they had to shut down the production of TRP. They cited the wood pulp prices and the lack of demand – separately. The rise of wood pulp is concerning but the the lack of demand even more so. Because this means that the production itself was not tied to wood pulp prices but that there are other expensive factors at play. The limited demand for the product would not sustain the production costs.
In May 2020, Tomoegawa Paper announced the closure of Shizuoka Plant machine #9.
In October 2020, it was announced that Sanzen Paper successfully acquired the rights to produce Tomoe River Paper. I suspect that this meant they could make thin paper with the same qualities as TRP and, importantly, use the name TRP. At this time, the paper was called Tomoe River Paper SUCCESSOR (Source: fudefan aka the paper hunter). That name did not stick and in July 2023, it was renamed Tomoe River S Paper. According to Sanzen, the ‘s’ stood for the company name and not ‘successor’.
Importantly, Tomoegawa Paper did not give the full production technique to Sanzen. The new company needed to develop their own method. Of course, it also means their method needs to be applicable to their own machines. Sanzen Paper says that no two machines can produce the same paper in a very mysterious way.
Tomoe River S Paper
Sanzen Paper produced very thin paper similar to TRP a long time ago (“ten years ago”). They used this as the basis for the development of TRSP. Their paper was selected by Hobonichi in a blind test as a replacement for the TRP. It is unclear whether they were selected first or they acquired the rights prior.
Regardless, Sanzen will be making TRSP for the Hobonichi techo and Hobonichi cousin 2024. The Hobonichi Weeks will still be using TRP for 2024, and will likely receive the sample paper with orders this year. By 2025, all Hobonichi books will have TRSP.
The TRSP is lighter than the TRP at 47 gsm. It also has higher opacity since Sanzen used white pigment to enhance the base paper. Do you remember the gaps in the paper I discussed above? Those gaps are now filled with white pigment. It’s likely that TRSP will be using white pigment (nanotechnology) at different nano sizes. This could allow bigger pigments to deposit in the interior of the base paper creating a denser middle portion. Ink will be prevented from seeping to the other side of the paper (bleed-through). In the Hobonichi article, Sanzen says that the way they created the opacity (the quality that prevents bleed-through, vs. translucence) is different from Tomoegawa Paper. If they are using the white pigment with nanotechnology, it will definitely prevent bleed-through, give the paper a whiter colour, and improve luster similar to a coating. They did not mention if TRSP is coated.
The Gentleman Stationer provided an in depth review of the Sanzen paper experience. The article says that the Sanzen paper is stiffer and smoother. Both qualities can be achieved with white pigment. The pigments offer more structure and a smoother surface since the gaps of the base paper is filled in. The pigments are small enough (maybe also the concentration) not to increase the paper weight. But also, if TRP relied on the multiple-coating and TRSP did not need thick coating, the paper weight would not be heavy in the first place.
How can Sanzen Paper afford to make TRSP?
This is a fear for all of us. Would Sanzen Paper remain afloat when Tomoegawa did not?
Sanzen Paper is owned by another company that belongs to Japan’s biggest paper company, Oji Paper. The backing of a conglomerate might be enough to at least give Sanzen a headstart. Plus, it would help to have a commitment from larger businesses like Hobonichi. And, a partnership with multiple local and international distributors. This is why I’m happy to see so many small businesses create their own bound planners using TRSP. It’s now become more accessible than before (when it was produced in limited quantities). The more TRSP is ordered, the longer Sanzen Paper will keep making them.
This is a massive gamble for Sanzen paper. But their business strategy seems to be paying off.
However, only time will tell.
xo, Paulina
PAPERJOYPH 