A traditional Japanese katana is typically extremely sharp. The blade is honed to a high level of sharpness, and its primary purpose is to cut efficiently and cleanly. However, the exact level of sharpness can vary based on factors such as the intended use of the katana and the preferences of the practitioner or swordsmith.

For a functional katana designed for cutting practice, such as tameshigiri (test cutting), it is generally expected to have a sharp cutting edge. The blade should be able to slice through targets, such as tatami mats or bamboo, with minimal effort and leave clean cuts.

It's important to note that handling a sharp katana requires caution, respect, and proper training. Serious injury can occur if the blade is mishandled or used improperly. Safety precautions, such as proper protective gear and supervised training, should be followed when practicing with a sharp katana.

If you are unsure about the sharpness of a katana or have specific concerns, it is recommended to consult a professional swordsmith or experienced practitioner who can assess and advise on the appropriate level of sharpness for your katana based on its intended use and your skill level.