I have tried to explore the relationship between the jangdan of Yeongsonhoesang and Sanjo. For this, a rhythmic proportion of the jangdan patterns and changgu patterns was examined. The conclusions are summerised as follows:
The basic pattern of the janggu pattern for jangdan in Yeongsonhoesang is ssang-pyeon-go-pyeon, and that of the Sanjo jangdan pattern is ssang-pyeon-go-pyeon-go-pyeon-go-pyeon which repeats Yeongsanhoesang jangdan twice. This appears to me that this phenomenon that ssang appears only once, during which the Sanjo jangdan repeats the Yeongsanhoesang jangdan, must have derived from the concept that only hap-jangdan (ssang) occurs in one Jangdan.
The proportion of the janggu stroke length (duration) of Yeongsanhoesang jangdan is as follows:
Manyeongson (Sangyeongsan) consists of 6:4:4:6; Sakyeongson (Seryeongson) 3:2:2:3;, Yeombuldodri 2:1:1:2. There are the combination of 'jang-dan-dan-jang (long-short-short-long) in its length (duration).
On the other hand, the proportion of Sanjo jangdan is as follows:
Jinyangjo comprises 6:4:6:4 6:4:6:4; Jungjungmori 2:1:2:1 2:1:2:1. These two types are the combination of jang-dan-jang-dan jang-dan-jang-dan'. Jungmori and Chajinmori are the same proportions which consist of 2:1:1:2 2:1:1:2. These two are the combination of 'jang-dan-dan-jang jang-dan-dan-jang. Hwimori comprises 3:3:2:4 which denotes 'jang-jang-dan-jeong.
This result shows that Yeongsanhoesang jangdan and janggu pattern of Sanjo jangdan, as well as the proportion of janggu stroke type are interrelated. Thus it can be said that the both jangdan, which seem to be complicate and various, are built up with the consistent rules, that is Sanjo jangdan is a variation of Yeongsanhoesang jangdan which is repeated twice. Based on this rule, a new jangdan can be generated. It is worthwhile considering that both jangdan might have rooted in the same ground and this needs to be examined further.