The number "4"
The number, four, is either pronounced as "shi" or "yon". Shi sounds similar to the Japanese word for death. This also holds true to all countries that fall under the Sinosphere like China and South Korea.
This doll is used as a charm in order to make wishes come true. When you buy one, it has empty eyes. You paint one of them as you make a wish. And when it comes true, you paint the remaining one. Hence, completing the set.
These carp streamers are traditional decorations for Children's Day, signifying good luck and a family’s wishes to have happy, healthy, and successful children.
STANDING TEA STALK ON A TEA
It is a sign of good luck given how rare this occurrence is.
Spider at Night
Typically, finding spiders at home on a morning is considered lucky. But finding them at night is unlucky and they are believed to be agents of demons.
Putting Chopsticks Upright on a Bowl of Rice
It is considered unlucky and disrespectful given that the Japanese only do this when offering food for the deceased.
Making a thousand cranes grants the owner a wish. Hence, they are a symbol of healing and hope.
Writing Someone's Name in Red
Japanese only write names in red if that person is deceased.
Stepping on the Borders of Tatami Mats
It brings bad luck to the family. This is because people used to put their family's emblems on it. Hence, stepping on the borders is seen as disrespectful.
Cutting Fingernails at Midnight
Since electricity didn't exist back in the olden days, cutting your fingernails in the dark might cause injuries.
I am a casual anime enthusiast, and a contributor on a certain KanColle fan page. Thanks to the aforementioned franchise and a long time of playing the game, I became interested on stuff about WW2 and started watching and reading materials, including anime, related to it. Hence, I am now slowly becoming a gunji otaku. During my free time, sometimes I write short stories but I never managed to finish anyone of them. :V