[dirtyroboto]

Like in the west, people don't open umberellas in the house but it's no big deal in Japan.
In the west people have forgotten why you don't open them in the house. It dates back to gas lighting and women's fashion of carrying a lace umbrella (for sun protection) and extending this to an indoor accessory. They soon found out the hard way that naked flame and lace do not mix.

Japanese who own dogs NEVER let the dog on tatami. and normally wash the dogs feet before letting it down on the floor. My friend lets her pooch into the garden then has to carry it to the shower to wash it's paws before it is allowed onto the floor. This happens alot.

There is also a long forgotten custom in Japan that you must never touch your pillow with your feet. Doing so, even brushing it slightly while moving it requires that you touch the pillow to your forehead three times while reciting a mantra.