The "shortie" pens from Japan that took the world by storm.
In the early part of the 20th century, the fountain pen business was booming. Pens were being made all around the world by hundreds of different manufacturers, consisting of many designs, materials, and colors. In Japan, the fountain pen had been readily adopted for use in daily business. Being very practically minded, the Japanese businessman would make use of the chest pocket on his starched white shirt and park his fountain pen there. But typical fountain pens of the day were rather large and would sit up high out of the typical Japanese shirt pocket. In the 1970's, Pilot came up with an answer for this: The Pocket Pen, "Shortie", or Long Cap. The basic configuration is a longer than usual pen cap, a long section, and a short body. What this ingenious design does is allow for the capped pen to fit inside shorter than average shirt pockets, but when the cap is posted the pen assumes a normal size for comfortable writing. When Pilot came out with this design, it was an immediate sensation. So much so, that Platinum and Sailor (the other two of the "big three" Japanese pen makers) also came out with their own version of the pocket pen shortly thereafter.
Naturally, with this pen design being such a big hit, many variations were produced. You would be able to buy them in a multitude of different plastic colors or types of metal, as well as a variety of trim styles. One of the most popular pens that Pilot is known for is the MYU (or short Murex). This pen follows the basic pocket pen design, but for one important difference: it has an integrated nib. The body, cap, and section were made completely of brushed stainless steel, making for a very tough pen. The nibs on these pens are very firm, so they don't appeal to a wide range of fountain pen users. But the sleek design, toughness, and dependability make it a great utility pen. The version with black stripes (MYU-500BS) is my all time favorite pen for appearance; I think it is a timeless modern design and it should be indoctrinated into the NY Museum of Modern Art.
Of the metal pocket pens, Pilot made them primarily out of stainless steel with a couple of models in sterling silver. In my opinion, one of the more attractive metal designs is the "cross hatch" pattern, which is a series of black etched lines with the length-wise lines closely spaced. It came in a full metal design, as well as a metal cap with black body. This was also done in silver with the venerable Cisele (or grid) pattern, that Parker made so famous with the model 75. No doubt Pilot copied Parker, as the 75 came out in the 1960's.
Regarding the nibs that Pilot installed in the pocket pen, there were basically four different designs (to my knowledge). One of them is the same 18kt gold nib that was used for the full size Pilot Custom series. I think it is one of the best nib designs today, for consistent smooth line control with just a touch of spring. Also, the sizes run small, which is a nice contrast to other makers that cater to larger nibs. The next is a more straight triangular nib design (unlike the slightly curved Custom nib) that protruded out from the section, with a flange of plastic covering the back end of the nib, which came in both gold/white-gold 14kt and 18kt nibs. There were two variations that had different flange shapes. The last nib type used is the stainless steel one seen on the colored MYU pens and the Volex (stainless steel version without integrated nib), with a shape that looks like it screws down into the section (it actually releases upon sliding out the inconspicuous retaining clip). It has a nice clean look with a black band around the chrome collar.
As for my personal collection, I have always been partial to Pilot (and metal in particular). But Sailor produced a few models that are extremely beautiful and very rare--it's nearly impossible to obtain them because of such low production. There's only one person (on FPN) I know of that has the two I'd love to own someday: The Arabesque and the Egyptian hieroglyphs.
So, without further delay, time for some photos: Gallery