The fudepen (筆ペン), also known as “Brush Pen”, is a cartridges-based writing instrument geared toward East-Asian calligraphy; in essence, an ink brush analogue to fountain pen. It consists of a pen nib that mimics the brush-like quality of the ink brush with either brush strands as in a normal ink brush or a soft felt tip similar to a marker; the nibs are fed by an ink reservoir. The ink used is unlike traditional calligraphy ink. It is designed to adhere well to modern paper, while traditional ink only adheres well to rice paper.

They are typically manufactured by Japanese companies such as Pentel, Sakura Color Products Corporation and Kuretake (art products). Fudepen is a pen having a shape imitating a brush in which ink is built in the shaft portion of the main body. As a history, in 1972 Fudepen has been developed, a company that cultivated improvement as a hit product for the first time, was the first successful commercial success is Wu Chi Pu Ledge. In 1972 it already stated that other companies were developing products.

Though it is common to have a structure that supplies ink contained in the shaft to the brush tip made by bundling thin synthetic resins, some luxury items use weasel fur. Some brush strokes are thick, brush strokes that can be used like a brush, and handling and maintenance are easier than writing brushes. Also, there are many brush strokes that are stronger than brushes. The hairs of the traditional brush are of some concrete animals. In the fudepen have been replaced by synthetic hairs.

It consists of a brush with an ink tank on the body that, with a slight pressure of the same, provides ink to the brush to be able to write or draw. The fudepen saves this work since it does not need to be washed after use. It is only necessary to cover it to store it.

In Japan, writing has traditionally been done with a brush, using a laborious process of manufacturing liquid ink from a solid ink bar. Later, ink that is sold liquid began to be used, but it is usually necessary to reduce it with water, or at least pour it into a container in order to be used. In addition, brushes should be washed carefully after use.

This system, very similar in concept to the pens invented in Europe, allows the Japanese to always have ready a brush with ink, portable, which can be used at any time and place. The inks are dyes and pigments. Some of them are cartridge type and can be replaced. The ink tank is usually disposable, it can be replaced or refilled when the ink runs out.

The fudepen ink is not like the ink used in traditional calligraphy. The traditional ink is not so concentrated and liquid at the same time, and if it is used in an offset type satin paper, of those used nowadays, the ink slips and barely adheres to the paper. However, the fudepen ink is more similar to fountain pen ink, achieving great adherence and very dark tones.

Types:
The tip of the pen-brushes is formed of a flexible material, sometimes made in a single block of a porous material and having the shape of a brush tip, sometimes made of hair, animals or synthetic. There are for example brush pens equipped with a tuft of sable hair.

The brush pen is powered by a (rechargeable) reservoir, an ink cartridge or a fixed ink supply for disposable brush pens.

When a tank is used (Chinese brands, as well as Kuretake, Monami), it is possible to fill either even, with water, to practice watercolor or adapted water-based calligraphy for example, Indian ink, walnut husks, colored liquid inks or any other mixture. To fill it, either dip it in the liquid and absorb it by successive pressure, when the handle is soft, or on some, use a worm. It is also possible to pour directly into the hole in the case of sleeve-reserve soft.

When the brush pen uses a refill, typically an ink cartridge (Pentel brand), it is usually for single use and produced by the manufacturer of the pen-brush. This ink is designed in this case for modern papers, unlike the Indian ink traditionally used on “rice paper” or tissue paper.

In the case of refill brushes supplied by the manufacturers or disposable, we can distinguish:

those intended for writing and drawing, mainly in black ink, some of which compete in presentation and price with fountain pens.
Those intended for coloring, existing with large tanks of different colors, often interchangeable.
In the case of tank brushes, the uses are relatively unlimited, since they can be filled with the liquid materials of their choice.

Depending on the model, the brush pen can be used for example calligraphy (Eastern or modern European), draw, color, etc. More and more cartoonists and illustrators use it for its quality of line and its simplicity of use, limited essentially to the wear of the bristles of the brush.