Noun
shinogi
On a Japanese sword or knife, the ridge line where the angle meets the flat part of the blade.
A flat or narrowing shinogi is called shinogi-hikushi, whereas a fat blade is called a shinogi-takushi. Source: Internet
However, swords could narrow down to the shinogi, then narrow further to the blade, or even expand outward towards the shinogi then shrink to the blade (producing a trapezoidal shape). Source: Internet
In the earlier picture, the examples were flat to the shinogi, then tapering to the blade. Source: Internet
Details such as the ridge line (shinogi) another distinctive characteristic of the Japanese sword, are added at this stage of the process. Source: Internet