Thursday, October 3, 2013

BaZi: The Zi hour controversy.

Zi hour controversy - New day starts at 11 pm or 12 pm?  

I wanted to write this since a long time ago but I have totally forgotten, until I saw Agnes comment recently. So thanks to Agnes for bringing this subject up.

I am an unfortunate person who was born around 11.45pm LAT in my hometown, so I have been researching into this subject quite extensively to figure out my correct Day Pillar. Though I am not entirely sure, I am convinced that my DM is Ji earth (which is the previous day) and not Geng metal (the next day).

There are 3 common positions BaZi practitioners take regarding Zi hour.

1. Many practitioners think the new day begins at the beginning of Zi hour, which is 11.00pm. There are only 12 Hour Pillars in a particular day, if a person is born at 11.00pm on Tuesday, he is considered to be born on Wednesday.

2. The second viewpoint is that the new day begins at 12.00 am, so Zi hour is divided in Early Zi hour and Late Zi hour. Early Zi hour belongs to the previous day and Late Zi hour will be on the next day. This method has 13 Hour Pillars in a particular day.

3. The third viewpoint is that Zi hour controversy will never be resolved, so Zi hour charts cannot be read. No divination for Zi hour - 子时不占

I take the second position, that Zi hour is divided into early Zi 子初 which belongs to the previous day and middle Zi 子半 12.00 am which is the beginning of the next day.

People who take the first position would argue that the ancient Chinese have always thought that the new day begins when Zi hour begins. That this is the traditional point of view. However, this is not entirely true. The time system had been changing since the Xia dynasty.

The book of Han (of Han dynasty) has a record that says:

Xia (dynasty) (used) the thirteen month as the true (first month), color still black, with PingDan (Yin hour) as the beginning.

Yin (Shang dynasty) used the twelfth month as the true, color still white, with the roosters crow (Chou hour) as the beginning.

Zhou (dynasty) used the eleventh as the true, color still vermilion, with the half of night (middle of Zi hour) as the beginning.

According to the history book, in Xia dynasty (2100 - 1600 BC), Yin hour was regarded as the beginning of the new day. While in Shang dynasty (1600 -1048 BC), Chou hour was regarded as the beginning of the new day and in Zhou dynasty which lasted from 1045 - 256 BC, the middle of Zi hour was regarded as the beginning of the new day. Now it is apparent that the ancient Chinese did not traditionally regard Zi hour as the beginning of the new day.

During Tang dynasty, Li ChunFeng (astronomer and mathematician), who was tasked with creating a new calendar system 麟德历 (Lin De Calender) wrote in the new book of Tang 新唐书, a phrase that says;

The ancient calendar divides the day, with the half of Zi as the beginning.

As far as I know, the knowledge of Life analysis began sometime in the Spring and Autumn period, around the time when Gui GuZi created the NaYin system. If back in those days they were using the middle of Zi hour as the beginning of the new day, how could we shift that to the early Zi hour?

If we look into Classical BaZi books, Master Wan YuWu, who authored SMTH (which I translate a lot in this blog), referred this subject to 革象新书 (The new book of Ge Xiang), a book from Yuan Dynasty that says:

If it is Zi hour, the half of the hour before the middle of the night belongs to the previous day, the later half after the middle of the night, belongs to today.

And therefore, I rest my case. 


  1. Thanks! Please let me add a fourth practitioner's view: There is an early and late zi hour, but the DM stays the same.
    I think "If it is Zi hour, the half of the hour before the middle of the night belongs to the previous day, the later half after the middle of the night, belongs to today" fixes the answer. Because it doesn't sound like affirmation on the natural succession of the days.

  2. The best way is to double check on your BaZi DM. Each DM has distinct characteristics.

    Ji Earth is more prone have effect to oily food.

  3. Dear Agnes,

    I don't really understand the 4th view,

    Does that mean a person born monday 23:00pm or tuesday 00:00am has the same day pillar?

    In this case the practitioner would take Chou hour as the beginning of the new day, which is ermm.. very ancient.

  4. Dear Anonymous,

    Well, I don't really feel very distinctively Geng or Ji and I don't particularly like oily food.

    I love all food that tastes good! I'm going to get some fried banana this afternoon.

    You want some?

    1. It easy to differentiate i feel, when yourself learn about bazi extensively. U are the best person to debunk this 2 theories.
      Geng is more solid and unyielding, Ji is more prone to cunning to take sides. Ji learns bazi more deeply. Their size is difference, Geng is well built and Ji more skinny, spiral. I think shouldn't take any adjusted time, take the actual birth time to read first.

    2. Fun stuff, as I am in a similar situation, although born after the midnight on wall clock time, but @ 22:57 LAT. And the day pillars are 丁酉 / 戊戌, and while I see that there is some diffrence between Ding and Wu, it is quite hard to differentiate it for me also. :D

      Really nice blog, thank you for your translations!

  5. Yes Trey..for example one is born on 26.10.2013 at 00.00 am- his DM is yi-chou with bing-zi hour, and at 23.55 is also yi-chou, but with wu-zi hour. I can't answer to your question because this is not my concept. Maybe the author's oppinion is that actually it is one and the same day - 26.10.2013, the zi hour falls within 23-1am period so DM doesn't change. And because I found from other masters that DM change too..and thus began to wonder which is right and what is the logic behind..

  6. Hi Agnes,

    This practice does not make sense to me, but to each, his own, whatever makes them happy!


  7. And to add the confusion, once on, Boyler argued that once upon a time in ancient China, Yin was regarded as the beginning of the new day. I can't remember his source of course, maybe when you continue your research on this topic, you can keep Yin as start of day in mind. =)

  8. It was Xia dynasty that began the day with Yin hour according to the book of Han, however, this is not relevant because BaZi was invented much much later afterwards.

  9. I'm another unfortunate case of being born at 2340 hrs and have been searching the web studiously for an answer as the DM differs greatly btwn 乙 & 丙

  10. Thank you for your article Trey!

    Just so I can confirm my understanding, let's say someone is born at 12:01am 6 Nov 1990 in singapore GMT+8 would his day master be Jia on EB Xu ... or Yi on EB Hai?

    I used bazi-calculator to determine an adjusted solar time of 11:12pm which will then be the 上半时 of the Zi 子时 which means that the date should be changed to 5 Nov?

    Is that the correct application of 若子时,则上半时在夜半前,属昨日,下半时在夜半后,属今日. ??

    Thanks again