What does the idiom "noon in Tatsumi" mean? Don't explain these words alone, I have already read them. I mean idioms made up of these words.

To be exact, this is not an idiom, but an old saying when calculating the fortune of yin and yang.

When traveling and doing business, the ancients often calculated to determine the time of action, so as to avoid misfortune, just as we often say "turning over the yellow calendar" (to put it bluntly, fortune telling). "Noon in Tatsumi" generally refers to the "auspicious time of the ecliptic" on a certain day, that is, from 8: 00 to 14: 00 now. It is generally believed that this period represents the most prosperous period for all things to grow. For example, in some ancient books, there will be a saying that "it is noon in Tatsumi" at the beginning, which actually means that this time is "auspicious", and most of them will follow the movements of the characters later.