Blog post -- Palace Secrets: Gender Prediction Chart

This picture (the big chart for predicting baby gender) is extraordinary. It is said to come from the Qing Dynasty's secretaries and helps pregnant mothers predict when they will give birth to a boy or a girl. The gray column at the top left represents months, while the yellow column at the top right represents ages. All the time and age involved are calculated according to the lunar calendar. The data prediction is based on actual cases, weighted average, then 5-day line weighted average, 10-day line weighted average, and finally accumulated monthly K-line and weekly K-line. It is rumored that in the old folk society, there was also a very rigorous formula to calculate the baby's gender. The formula is as follows: (49 + the month of conception in the lunar calendar - the mother’s age in years + 19) % 9. If the final remainder is an odd number, it's a boy; otherwise, it's a girl. The biggest similarity between these two formulas is that their accurate prediction rate is both 92.3%, which is quite precise.