A BaZi (八字) has 4 pillars (Year, Month, Day and Hour). Analysing a BaZi is to analyse all 4 pillars together. For this reason, a BaZi is also known as Four Pillar (四柱). To analyse a BaZi, you need to know the year, month, day and time of birth. However, in many situations, you do not know the time of birth. In other words, you do not know the Hour Pillar. The question is: can you still analyse a BaZi without the Hour Pillar? This article explains why you cannot analyse a BaZi without the Hour pillar.
To analyse a BaZi, certain pre-works have to be carried out first before any analysis can be carried out. Without the Hour Pillar, these pre-works cannot be carried out.
The first pre-work is to check for combinations and transformations in a BaZi. The purpose is to determine the true identities of all elements in a BaZi. Without the Hour Pillar, you would not know what Ten Gods (十神) are in the Hour Pillar and you also cannot check for combinations and transformations.
The second pre-work is to determine a BaZi structure. There are 6 types of BaZi structure, please see BaZi 2. Without the Hour Pillar, you would not be able to determine a BaZi structure because you are not able to perform combination and transformation.
The third pre-work is to determine the favourable (喜神) and unfavourable Ten Gods (忌神) of a BaZi. The determination of favourable and unfavourable Ten Gods is essential in BaZi analysis. Without the Hour Pillar, you would not be able to determine whether a Ten God is favourable or unfavourable because you are not able to determine a BaZi structure.
Some analysis may use the element in the Month Branch (i.e. simply looking at the season of birth) to determine the favourable and unfavourable Ten Gods. Using this approach, you would not be able to determine the favourable and unfavourable Ten Gods correctly for special BaZi structures such as Overly Strong Structure (专旺格), Fake Overly Strong Structure (假专旺格), Overly Weak Structure (从格) and Fake Overly Weak Structure (假从格), and for certain Normal Strong Structures (正旺格) and Normal Weak Structures (正弱格).
For those interested to learn BaZi, please see BaZi course.