Why cant you stick your chopsticks vertically in rice in Japan?

Answer 1

While it may minimize the transition time between the voracious gobbling of food and intermittent sipping of aTsingtao or cup of cha, stowing chopsticks in this way is neither prudent nor polite.

Meaning: It's a harbinger of death.

Just as the number four, si (四), is considered inauspicious for its homophonous relation to the word si (死), meaning death, the sight of two upright chopsticks in a bowl is reminiscent of the incense sticks that the Chinese traditionally burn in veneration of deceased loved ones.