Chinese Daylight Saving Time: How Forgotten History Impacts Modern Bazi Calculations
A Neglected Historical Detail
From 1986 to 1991, China's daylight saving time worked like this: from mid-April to mid-September each year, all clocks nationwide were advanced by one hour. For example, in 1987 it was April 12 to September 13, and in 1988 it was April 10 to September 11.
What does this mean? Suppose you were born on June 15, 1987, at 2:30 PM - that's exactly what the hospital would record on your birth certificate. However, since this was during daylight saving time, this "2:30 PM" was actually time that had been advanced by one hour. From an astronomical perspective, the true standard time should have been 1:30 PM.
For Bazi calculations, this one-hour difference is no small matter. It could lead to incorrect time period identification, and in some critical cases, even affect the day pillar, ultimately making the entire Bazi chart inaccurate.
How We Solved This Problem
Facing this historical legacy issue, we designed an intelligent identification system.
The system automatically determines: Are you a Simplified Chinese user? Does your birth date fall within the 1986-1991 period? Is the specific date within that year's daylight saving time period? Only when all three conditions are met will the system suggest you might need daylight saving time adjustment.
The benefit of this approach is that over 99% of users won't see any related features, keeping the interface clean. For those 36 million potentially affected users, the system clearly displays a comparison between original and adjusted times, with the entire process being completely transparent and allowing users to choose whether to make adjustments.
However, what we care about most is data security. The system uses an "original data unchanged, adjust during calculation" approach, where every time point you enter is completely preserved, and no adjustments overwrite the original records.
The Technical Value and Humanistic Significance Behind It
In technical implementation, we adopted "original data unchanged, adjust during calculation" architecture to ensure data traceability. The system processes time corrections by priority and presents adjustment features in the most streamlined way when detecting potential impact.
This feature serves 36 million real life stories. In traditional numerology, a one-hour deviation could completely change Bazi interpretation. Using modern methods to correct historical deviations is a modern expression of traditional culture's precision requirements.
Many users have no idea China once implemented daylight saving time. Through this feature, they get accurate results while learning overlooked history. This is our desired effect: technical rigor with humanistic warmth.