One of the reasons we focus on systems like Wen Wang Gua 文王卦
Regarding Wen Wang Gua - I have 0 experience with this method. I only have Vincent Koh book (I ching wisdom revelead) - it was recommended here.
I may be able to provide some info / suggestions when I get experience (reading the book, learning the method and trying it e.g. 200+ times).
One of the reasons we focus on systems like Wen Wang Gua 文王卦, is because the text, in my humble opinion is just not suitable for complex questions.
When I asked Yijing this year, question was like:
What will happen if I change method of divining?
{ sometimes I was asking complex questions and I was thinking about using system from Vincent Koh book which is Wen Wang Gua OR totally different system, albeit "synthetic", in other words ignoring "text" }
I got
48.3.5 -> 7
Back then I was using Joseph Yu, Wilhelm and psychic-revelation (only hex descriptions) for divination.
If I go to
http://www2.unipr.it/~deyoung/I_Ching_Wilhelm_Translation.html#48and check judgement
THE JUDGMENT
THE WELL. The town may be changed,
But the well cannot be changed.
It neither decreases nor increases.
They come and go and draw from the well.
If one gets down almost to the water
And the rope does not go all the way,
Or the jug breaks, it brings misfortune.
Initial hex tells me that Iching will provide you always the same "signal", in other words well "it neither decreases nor increases".
{ It makes sense, because basically Iching is 2**12 OR 64*64 -> 4096 combinations (the same amount of "signal" from spiritual world). }
But If I make mistake (hasty way of making interpretation or being careless) then it will be misfortune.
Changing lines are positive (wilhelm text), however ending hex 7 Shi could be interpreted as "mobilization".
In other words I will have to learn new method

So I decided to just continue with "old ways" and try to master it (Yijing is easy to learn, hard to master).
On the other hand, Vincent Koh inside his book provides some framework/system for some inquiries e.g. finding missing thing, divining gender of child etc.
Then in this scenario it is possible that Wen Wang Gua is more efficient way instead of "classic text interpretation".
Also regarding hex 48 Jing.
Wilhelm judgement is different from Iching123 judgement/text.
Inside
https://www.iching123.com/48_text.htmI have judgement:
Jing (the well): The townscape has changed but the well remains unchanging. The water of the well neither decreases nor increases, even if people come and go in Jing (drawing water from) Jing (the well). However drawing is done in such a greedy way that the well nearly runs out of water; the rope has not reached the top of the well yet, the bucket breaks, which is of an ominous omen.
This could explaing why Jing doesn't possess any virtues:
Overview:
The well provides water to all people. However people fight each other for it and become estranged, as suggested by its changing hexagram Shi He (21) and inner hexagram Kui (38), alienation. The bucket breaks before it reaches the top of the well, which is ominous. It is not the fault of the well but rather of the drawer.
Owing to its failure at the last moment, all four virtues: origination, smooth progress, advantage and persistence, become meaningless; thus hexagram Jing possesses none of them.
It could basically mean that Wilhelm explanation of Jing 48 could be incorrect.
Does it means you can't have results if you use Wilhelm text + Joseph Yu for interpretation?
Not really, Iching will automatically "auto-detect" which interpretations you use and give appropriate hexagram and changing lines.
{ This is also why I am using Wilhelm for interpretation of OLD divination, instead of Iching123; basically I was not aware of Iching123 then and divination was built for Wilhelm+Joseph Yu }
But this doesn't necessary mean, that Wilhelm interpretation is superior in my opinion.
I would say it is much less "in-depth" to Iching123 e.g.
- doesn't provide information which virtues hex have (only mentions that 1 Qian and 2 Kun have 4 virtues).
- no info about inner hexagram
- no info about changing hexagram
- no info about interactions between lines inside changing lines or inside hexagrams e.g. Sheng 45
- no image in moving line text
- no lines deduction
etc etc
There are hints to it, if you look at first and second Hexagrams, there is text valid if all 6 lines change at the same time. So we can see how one should approach the system, as that is the only condition in it where we can see text for more then one changing line presented. We can see that text has nothing to do with the line someone would take if they just use simple method for choosing the premade text for one of then. Neither it is the meaning combine, its entirely different text, very logical since the Hexagram changes to something entirely different then it would from each individual line.
As of course, if the system wanted to show you line 3 changing, while would it also show you so many other lines moving... And why would they write the text for 6 changing lines in Hexagrams one and two, if you could find that text just by choosing one of the other lines...
I suppose the above paragraph refers to "Master Yin" way of moving lines interpretation.
Master Yin
According to Alfred Huang, Master Yin handed down these rules for interpretation when there is more than one moving line.
1. If there are two moving lines—one yin and the other yang—consult only the yin moving line.
2. If the two moving lines are both yin or both yang, consult the lower one.
3. If there are three moving lines, consult only the middle one.
4. If there are four moving lines, consult only the upper of the two nonmoving lines.
5. If there are five moving lines, consult only the other, nonmoving line.
6. If six lines are all moving, consult the Decision of the new gua, the approached gua.
7. Since there is a seventh invisible line in the first and second gua, Qian and Kun, for these gua consult the seventh Yao Text, called All Nines or All Sixes. [If six lines are all moving.]
I just use this method as "support". I still try to interpretate all moving lines
In my experience, if you have only 1 moving line, then you can stick and only interpretate it.
For more changing lines, I interpretate all of them, but give more weight to lower line if I have 2 yangs (2 moving lines scenario) or to central one (3 lines) etc
In other words, it is something like "shortcut" what will happen.
If there are 4 or 5 moving lines, then "virtual line" will provide you "shortcut".
PS. I may be able to write review of this Iching123 book or write down all guides / tricks / tips regarding Iching. But this will take some time (busy now with other stuff)