In some regions, there is a view that it is good manners to wear Mofuku at Tsuya, however, it is, generally speaking, impolite to attend a Tsuya dressed in Mofuku (It comes from a view that wearing Mofuku indicates that a funeral has been expected, which is thought to be impolite.)
地域により、通夜も喪服が礼儀であるとの見解もあるが、一般的に通夜へ喪服で参加することは失礼にあたる（喪服だと葬儀を予期してたようで失礼にあたるという考え）。