Before Rikyu, lighting of the teahouse came through 2 or 4 sliding doors at the veranda and it was "one-way lighting," but Rikyu enclosed the teahouse with a mud wall first and then made a window anywhere it was necessary. (invention of the art of "enclosure").
師の紹鷗まで茶室の採光は縁側に設けられた2枚引きあるいは4枚引きの障子による「一方光線」により行われていたが、利休は茶室を一旦土壁で囲いそこに必要に応じて窓を開けるという手法を取った（「囲い」の誕生）。