The Shima-Ken Joint that is developed by Kenshiro Shimazaki who is a genius developer at Fly Fishing is living in Japan has enough strength in the joint (knot) two different diameters of line together.
In generally, such joint is easily cut at fine thread which means tippet (i.e. 6X is cut at Joint 0x and 6X.). And the strength is weaker than the original one. It is shown because the knot at hook is stronger than such knot.
The reason of this phenomena is simple.
Most knots are twisted or winded around between the threads. (Albright knot is also great knot for two different diameters of line together.)
In generally, such joint is easily cut at fine thread which means tippet (i.e. 6X is cut at Joint 0x and 6X.). And the strength is weaker than the original one. It is shown because the knot at hook is stronger than such knot.
The reason of this phenomena is simple.
Most knots are twisted or winded around between the threads. (Albright knot is also great knot for two different diameters of line together.)
The power to form the unit for a thick thread is too strong for a fine one.
Therefore a fine thread is wringed and pressed by thick one.
The strength of pressed thread is weaker than non pressed one.
Therefore a fine thread is wringed and pressed by thick one.
The strength of pressed thread is weaker than non pressed one.
Some knots
This photo shows that the thick thread involves fine thread which pressed
This photo shows that the thick thread involves fine thread which pressed
Uni knot
Double-tripple surgeon's knot
Shima-Ken Joint
Albright knot
The thick thread involves fine thread and it is pressed except Shima-Ken Joint and Albright knot
Double-tripple surgeon's knot
This knot is advocated by Kenji Sugisaka who is a great fly fisher. However, this knot cannot escape from the press of thick one.
Shima-Ken Joint
Detail is described in this page. and secret is prepared for nymphing that is unique.
Albright knot
This is great and popular knot for two different diameters of line together.
However, a secret described in abobe is not hidden in this knot.
However, a secret described in abobe is not hidden in this knot.
On the other hand, knot at hook is using appropriate power to joint, therefore it is not so pressed than such and holds the original strength.
Structure of Shima-Ken joint
Thick thread
The end of the thread has a knot by eight knot. The purpose of this knot is resistance for fine thread.
The construction of hook eye for Japanese fishing hooks is special that is not circle but pressed to form a resistance for knot that is called "Chimoto".
The knot end of the thick thread for Shima-ken joint has same function as "Chimoto"
The knot end of the thick thread for Shima-ken joint has same function as "Chimoto"
Fine thread
The fine thread is knotted to thick one with uni knot.
The structure of this knot is same as "Uchikake-musubi" that is a knot with "Chimoto" for hook.
