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Kizu - Flaws seen in Japanese Swords

There are many types of flaws in Japanese swords. Some like Kirikomi are not considered a problem, others like Hagire are considered a fatal flaw. Some of these flaws are caused by damage due to poor care of the sword, other flaws are a result of poor workmanship of the smith. Since the blade has been polished many times the flaw might now start to appear. The list below is only a partial list and covers some of the more common flaws. Some flaws can be overlooked if the blade has significant age.


A crack in the hardened edge of the sword at or near 90 degrees. This is a fatal flaw. Hagire can be hard to see and often do not appear until the final steps of polishing. To look for a hagire, look for a scratch on the blade running through the edge. Then look for the scratch in the same place on the other side. If a sword has been bent there are often hagire.


This is a piece of steel that has been added to the blade to fill in a Ware, pocket or other flaw. They can be seen to look like an island of steel.


This is an actual cut in the blade, usually on the Mune, from another sword. These marks are not corrected by the polisher and appear toward the front of the Mune. this is not considered a problem and is not removed during polish.


There are wrinkles in the surface steel as a result of a sword being bent and or straightened. They look like cross-hatched lines or have a thin tin foil look to the blade surface. Even if the bend has been straightened, the wrinkles can still be present. These require a full polish to correct.


Ware are openings in the steel along the weld line and can be a result of a poor weld or a very old weld. The openings follow the hada or grain pattern since that is the weld line.


These are weld lines that are opening along the Mune or back of the sword.