The other side of the Isshinryu picture is speculation but seems reasonable. Whether in his role as Sumuchi, Shimabuku Tatsuo ever consulted his oracles (books like the I Ching) regarding Isshinryu.
This likely originated in China, where his uncle had studied the arts involved. It seems he learned these arts while young Jeff Perkins Sensei shared videos of the books including the I Ching that Shimabuku Sensei did consult in his role as Sumuchi.
During different periods of his lifetime, he was a farmer, tax collector, bodyguard, horse and cart teamster, karate instructor and sumuchi (fortune teller).
Prior to his death on May 30, 1975, Tatsuo was still doing fortune telling. Sumuchi is from the Uchinaguchi (Okinawan language) or dialect hogen but fortune tellers are also called sanjinso in Japanese. Sanzinso literally means “three phases of life” or “Three social trends,” which are the past, the present and the future.
Long before Tatsuo studied karate, he was learning to be a sumuchi from his uncle Ganeku Shinko who later would teach the young Shimabuku Shaolin-zi (Shorinji) style of karate that he learned in Fukushu (Foochow) China.
Shimabuku learned to be a sumuchi from his uncle on his mother’s side who lived in Agena village which was near Chan village. Ganeku was a school principle for a school at Isshikawa, a town located in central Okinawa. Years earlier Ganeku had traveled to China and learned to be a fortune teller. In the main Okinawan Shuri and Naha dialect, a fortune teller is called sumuchikuya or sumuchi/shimuchi for short. ‘Su” means book and ‘muchi’ means person so sumuchi is a ‘Book person’ a term used in Okinawa for a fortuneteller.
The reason these fortunetellers are called sumuchi is because they use books such as the I Ching, Chinese Almanac, Chinese books on Astrology and Feng shui.
A sumuchi is well versed these ancient books and the "I Ching" (The Book of Changes), a classic Chinese book of divination, is used to consult to advise their clients in the proper course of action to take in certain phases of their lives. Okinawan Sumuchi are held in high esteem and are respected for their knowledge of old customs, history, traditions and events. This knowledge is passed from Sumuchi to apprentice and Tatsuo learned from Ganeku.
Sumuchi are also called sanjinso or sanzinso which literally means “Three phases of life” or “Three social trends,” which are the past, the present and the future. Sumuchikuya/ sumuchi/shimuchi and Sanjinso are all in reference to fortunetelling. Another subject Sumuchi perform is Feng shui.
Fungshi (literally "wind" and "water") in Okinawan hogen and Feng Shui in Chinese is the ancient art of placement which addresses environmental energy imbalances of yin and yang. Fungshi which originated in China aims to promote balance and harmony between one’s living and one’s working environments. It can be described as the study of the relationship between humanity and earth and Fungshi is still deeply rooted in Okinawan life. The ancient Shuri Castle layout was based on Fungshi .
The interview continued and focused on Tatsuo Shimabuku’s first martial arts teacher, his Mother’s bother, Ganeku. Ganeku taught Tatsuo Shimabuku to be a sanjinsoo or sumuchi (fortune teller). “Sumuchi” is the term used in Uchinaguchi (Okinawan dialect). Ciso unvealed the Sumuchi books used in his Father’s practice as he did for us in 1994. As explained in 1994, Ciso stated that the books were over 100 years old and are written in kanji (Chinese characters), which few today on Okinawa can read. He made reference that a “college boy” could not read these books but that he could, as taught by his Father. He explained how these books are very rare and even in his Father’s day, only a few could understand them. Ciso stated that his Great Uncle Ganeku spent two years in China where he was taught Sumuchi and Shorinji (Shaolin Temple Boxing) by two individuals “Kushi” and “Mushi” (Okinawan hogen pronunciation, “Koshi” and “Moshi” in Japanese). He says Ganiku was a High School principal by profession in Ishikawa Village but lived in Agena. Ciso produced sticks and a compass that are used in the Sumuchi process. He explains that the compass is used for the planning of tombs and houses (the direction of the entrances of houses and tombs are very important. A Sumuchi was usually consulted before construction). We left Ciso early, not wanting to push his health, to return on another day before we left the Island.
he asked Ciso about Tatsuo Sensei's sumuchi books. Ciso talked to us about learning fortune telling from his father and his father learning from Ganeku who was Tatsuo's uncle on his mother's side
Shimabuku Cisco demonstrating how his father would meditate.
Of course this does not explain much of what the sumuchi role involved.
So I first began by searching for ‘Sumuchi’ on the internet, however all I found was the role associated with Shimabuku sensei, and no other explanations. So the perhaps the term ‘sumuchi’ was Okinawan and as everyone uses Japanese on Okinawa today I thought to try the Japanese term ‘Sanjinso’ combined with Okinawa. I did find this.
Playing a lesser role than the kaminchu and yuta in Okinawan shamanism, the sanjinso is a fortuneteller or diviner who determines personal fortunes. Men have exclusively held this profession. Unlike the yuta who possesses supernatural powers, the sanjinso makes his prognosis from the lunar almanac, I Ching, and other books on Chinese occult lore. The sanjinso is consulted when selecting auspicious days for engagements, marriages, funerals, buying and selling houses, moving, and traveling.
Which does not offer much more information.
Nor do we have any writings from Shimabuku Sensei about his role as ‘Sumuchi’.
Perhaps a clue can be found in his use of the I Ching. It is a famous long lived Chinese tradition, as a means to interpret change as it occurs. I studied it a bit as a hobby in University, as it interested me.
The I Ching Hexagrams
The I Ching does not tell the future. It is a collection of observations made over a very long time about change, using various means to gather information on change as it happens. It’s roots go back as far as 1,000 B C. Very old indeed. It represents long term observations on Change.
The individual interpreting those changes, uses a large text with possible interpretations of the changes made. It is then from their observations on those interpretations in the I Ching that they offer opinions about what they find. So change, recorded observations of change, interpretation about what those interpretations offer. This is what happens when the I Ching is used.
I speculate whatever other texts are used might be in a similar fashion to answer the questions posed. Skill understanding change, that increases with time.
If his observations prove successful to others, then his reputation increases. Apparently people found his answers most useful.
Of course this opens thought on whether he did the same about the changes he participated in with his karate too.
Unfortunately this can only be speculation.
However it was not magic, IMO. Rather gained skill at understanding that the nature of change is the reality of the universe.