Sōsuishi-ryū (双水執流), known more fully as Sōsuishi-ryū kumiuchi koshi no mawari (双水執流組討腰之廻), is a classical Japanese grappling tradition of the kind usually gathered under the later label of jūjutsu. Its longer name announces its character: kumiuchi (組討), the close grappling of warriors who have closed to arm's length, and koshi no mawari (腰之廻), the work done around the waist and centre, including the use of the short sword at grappling range. Founded in the seventeenth century and preserved for generations in the Fukuoka domain of northern Kyūshū, it descends from one of the oldest of all jūjutsu lines, Takenouchi-ryū.
The founder
The tradition is attributed to Futagami Hannosuke Masanobu (二上半之丞正信), a warrior active in the seventeenth century. His exact dates are not securely recorded, and outside the school's own accounts his life is thinly documented, a common situation for the founders of koryū from this period. The unusual name of the school is explained within its own traditions rather than by any outside record, and those explanations are best read as the school's account of itself, not as established history. What can be stated with more confidence is the kind of art Futagami transmitted and the line he drew it from.
When distance has gone, the contest is decided by structure and position, not by the reach of the blade.
Descent from Takenouchi-ryū
Sōsuishi-ryū belongs to the broad family of schools that descend from Takenouchi-ryū (竹内流), the sixteenth-century tradition often described as the oldest organised jūjutsu in Japan. The clearest sign of that inheritance is in the name itself: koshi no mawari (腰之廻) is the very term Takenouchi-ryū uses for its close-quarters work with the short sword, and its reappearance in the full title of Sōsuishi-ryū points directly back to that parent line. The standard reference works on the classical fighting arts place Futagami's grappling within this Takenouchi descent. The relationship is therefore one of genuine lineage rather than loose resemblance, though, as with most koryū, the precise steps between the parent school and the new one are clearer in outline than in every detail.
What the school teaches
At its heart Sōsuishi-ryū is a grappling art. Its forms address the moment when distance has collapsed and two armed or armoured men are locked together, and they work through throws, joint locks, chokes, pins and restraints, with atemi (strikes) used to open the way for a technique rather than as ends in themselves. The koshi no mawari portion brings the short sword into this close work, both as a weapon to be used and as a threat to be controlled when an opponent reaches for his own. Alongside the empty-handed and short-sword grappling, lines of the tradition have preserved further weapon study, and the school is remembered as a complete grappling curriculum rather than a collection of isolated tricks. The emphasis throughout is on structure and position at the point where, as is often said of its parent school, distance disappears.
The Fukuoka tradition
What gives Sōsuishi-ryū its particular history is its long association with one place. The school took root in the Fukuoka domain of Chikuzen province, on the island of Kyūshū, the territory of the Kuroda lords, and it was carried there across the generations of the Edo period. Fukuoka was unusually hospitable to the classical fighting arts: the same domain preserved Shintō Musō-ryū, the great school of the staff, so that Sōsuishi-ryū grew up in a region where koryū were valued and kept. This regional rootedness, rather than a spread across the whole country, is the characteristic shape of the school's transmission, and it explains why Sōsuishi-ryū is still most strongly identified with Fukuoka today.
The school today
Sōsuishi-ryū continues to be transmitted in the Fukuoka area, and it is counted among the classical grappling schools that have survived into the present. Like many koryū it is carried by a small number of practitioners rather than a large organisation, and its survival rests on the patient handing-on of forms, etiquette and old scrolls within a regional line. The honest position is that the founder and the earliest generations remain lightly documented, while the school's descent from Takenouchi-ryū and its long life in Fukuoka are far better attested. What survives is a grappling tradition that still teaches, in a recognisably old idiom, the close, structural fighting from which Japanese jūjutsu as a whole grew.