A traditional katana, while renowned for its sharpness and cutting ability, is not designed to reliably cut through heavy armor, particularly plate armor. The construction and purpose of the katana were not specifically tailored to defeat heavily armored opponents.

Armor, especially plate armor, is designed to withstand and distribute the force of various types of attacks, including cuts and thrusts from bladed weapons. It typically consists of multiple layers of metal plates, reinforced joints, and padding, which provide effective protection against cutting attacks.

While the katana's sharp blade and cutting technique can cause damage to less protected areas or weak points of armor, such as gaps or joints, effectively cutting through the solid plates of armor with a single strike is highly unlikely.

Historically, swords like the katana were more commonly used to exploit the vulnerabilities of armor, such as targeting exposed areas or using techniques that focused on thrusting or blunt force rather than cutting through the armor itself.

If you are interested in historical armor and weapons or martial arts involving bladed weapons, it is recommended to seek proper training from qualified instructors who can teach you the appropriate techniques, safety protocols, and the strengths and limitations of each weapon.

Always prioritize safety and follow the laws and regulations of your jurisdiction when considering the use of any weapon