San Yuan derived Feng Shui such as Xuan Kong Fei Xing (Flying Star) has a time component.
A 180-years block is divided into sub-blocks of 20 years called period.
For example the 20-years time span between the 4th Feb 1984 and 3rd Feb 2004 is known as Period 7 while the 20-years time span between the 4th Feb 2004 and 3rd Feb 2024 is known as Period 8.
A house that is completed and occupied during Period 7 is known as a Period 7 house and acquires a “qi” distribution or energy map distinct to that period. A house that is completed and occupied during Period 8 is known as a Period 8 house and has a different “qi” distribution or energy map as shown below.
The date of completion is usually used to determine the Period of the house. For example a house is considered a Period 8 house even if construction commenced in 2003 (period 7) but completed and first occupied in 2005 (period 8).
Please note that some lineage uses the starting of construction date to determine the period of the house. Most schools however use the completion date.
But what is the period of the house if it was completed in 2003 (Period 7) but left vacant for two years and then occupied in 2005 (Period 8). Is this a Period 7 or is this a Period 8 house?
This is a hair splitting question and you are likely to get different answers from different practitioners.
For me I take the completion date and the date that it was first occupied to determine the Period of the house. If the house was completed in 2003 and first occupied in the same year, then I would consider it a Period 7 house. However if it was completed in 2003 but first occupied in 2005, then I would consider it a Period 8 house.
Why? This has to do with the trinity concept where an event is determined when three conditions are present. When a house is completed it has already met the heaven and earth conditions. The third condition is man and this is met when the house is occupied.
So, for houses completed just before the change to a new period, I would urge the occupants to move in if the energy map is auspicious and matches with the internal layout and external feature. On the other hand if the energy map and layout are better suited for the next period then I would urge them to delay the move in to the next period.
In Malaysia, it is quiet common for the main contractor to build temporary living quarters at the site for their workers. These quarters are not sturdy and do not last for long. When the houses are half completed i.e. when the four walls and roof are up, some contractors would move their existing or new workers into these half completed houses.
The question is, if the workers occupy these half completed houses in period 7 prior to the actual owners moving into these houses in Period 8, are these Period 7 or Period 8 houses?
This is really splitting hair! And it will take a long of research and case studies to arrive at an answer. For me I still use the completion date and occupancy date to determine the period. In the cases above the house was not yet completed in Period 7 even though it was occupied by the contractor’s workers. For me it is a Period 8 house.