When kimono were worn every day, they could be tied with a great variety of obi. Many of the informal obi styles, like the soft, black-satin faced chūya obi, have disappeared.
(Chapter 4: Kimono in Modern Japan > Types of Obi, pg 186)
There is a vintage kimono shop in Kyoto, for example, that has shelves piled with soft obi faced in black satin. These are pliant hand-painted silks rather than brocade, worn through the 1930s as casually stylish everyday clothing. These obi are friendly, not forbidding. They are also obsolete.
(Chapter 4: Kimono in Modern Japan > The Feminist Critique, pg 140)
This style of obi is called chūya (noon-night), because it was always black satin on one side, a color on the other. I suspect that this style may have originated among geisha (who influenced so many kimono fashions) because, upon rising around noon, they could well have worn such a thing until they changed into elaborate brocades for their evening's work of entertaining. I have never read anything that suggests this origin, but the designs on so many of these old chūya obis are often quite chic - just the sort of thing one readily imagines a geisha wearing.
(Liza Dalby's Kimono, Footnote 4.16, pg 342)
昼夜帯 Chuuya (Day Night) Obi still used for modern dance costumes. Reversible and nifty.
(13,650円, from Y!Japan here)
They show up often in Edo-era prints from Ikeda Eisen.