It may be a tad ridiculous to think that Pilot, which makes the E95S (the last man standing of all the Japanese long short pocket pens), didn't really know what it was doing when it made its first Japanese-style pocket pen, but it's true. Here is an example of a Pilot Short, more specifically a Pilot Short S-150SS, Pilot's first iteration of a Japanese pocket pen.

A Pilot Short S-150SS
At first glance, the pen is a tad short at 4 5/16 inches capped, but it's a comfortable writer when posted, though you can feel a bit of back weight from the steel cap and part of the barrel. The pen also sports a much shorter section than the later Pilot Elite pocket pens. I find myself having to hold the pen much further up the pen than I would normally, which is something I don't do with my Pilot E95S. The cap and barrel of the pen are opposite of how they would be on a normal Japanese pocket pen, with the barrel being longer than the cap. There is one feature that makes this pen unique amongst Japanese pocket pens, and most other fountain pens...
Here is a picture of the pen posted:

And here is another picture of the pen posted:

If you couldn't tell, this pen telescopes to make it longer. Telescoped, I can feel the weight of the cap and metal portion of the barrel. When the pen first telescoped on me, I thought that there was a problem with the pen, and I was ready to shellac the telescoping portion in place until I realized nothing was wrong with the pen. I personally don't really care that the pen telescopes, but it is a tad annoying when it happens when I'm trying to uncap the pen. Writing a draft of this blog with the pen, its nib is feedbacky due to it being a Japanese fine, and is supposedly gold with the hallmark hidden under the hood of the section. Overall, the pen is interesting though I can see why Pilot eventually came out with the Pilot Elite pocket pen.
Works Cited
ChrisR. 2024. “Pilot Pocket Pens – ChrisR.” July 20, 2024. https://chrisraper.org.uk/blog/pilot-pocket-pens/.
“PenHero.com - PenGallery - Pilot Short S-150SS Fountain Pen With Telescoping Section C. 1966-1969.” n.d. https://www.penhero.com/PenGallery/Pilot/PilotShort1966.htm.