A large, varied, and usually informal style of kimono.
It is characterized by an all-over pattern repeating that can flow in any direction or follow any theme. Older women tend to wear smaller, subdued patterns, while younger women tend to wear larger and more bold patterns. Depending on the material, a Komon can range from semi-formal (when made of synthetics of silk) all the way down to "fudangi" house-wear (woven wool).
In older vintage pieces, aspects of Komon may be combined with design cues from other styles of kimono, such as blending the all-over pattern of a Komon with the hem-only design of an Iro-Tomesode with a crest, or the hem-sleeve-and-shoulder dyeing pattern of a Tsukesage. For formality's sake, these kimono should be treated as the non-Komon half of the hybrid (such as treating the previous examples as an Iro-Tomesode and a Tsukesage, respectively).
At one point in history, Tokyo (then known as Edo) became a major point of Komon production. One style that was particularly attributed to Edo was one consisting of designs formed entirely from tiny dots. These Komon, now referred to as Edo-Komon, were made through a form of 'resist dyeing' that called for applying rice paste to the kimono with a metal stencil, and then dyeing the fabric. When the rice paste was cleaned away, it left white un-dyed dots in its place. Though this was historically used with indigo dye, modern examples may use any number of colors and modern dyeing techniques.
From a distance, an Edo-Komon may appear to be a solid color without a pattern, and the dot pattern may only become apparent up close. For formality, an Edo-Komon should be treated like an Iromuji. They are very versatile, and depending on how they are styled with obi and accessories, can be worn for a wide variety of occassions.