Yes, it is possible to fight with a katana using one hand, although it is not the primary or intended method of wielding the sword. The design and balance of the katana make it most effective when used with both hands, as this provides better control, leverage, and power in strikes.

However, there are situations where a samurai or trained swordsman might need to employ one-handed techniques with a katana. These situations might include fighting in close quarters, when a second hand is occupied or injured, or when speed and agility are prioritized over power and reach.

Using a katana with one hand requires specialized training and technique. The grip and hand positioning may need to be adjusted to compensate for the loss of the second hand. The samurai might focus on using quicker, agile movements, precise thrusts, or swift slashes to exploit openings or weaknesses in the opponent's defenses.

It is important to note that one-handed use of a katana requires additional strength, dexterity, and control compared to two-handed use. It also limits the ability to generate the same level of power in strikes. Therefore, one-handed techniques with a katana are typically employed in specific circumstances or as a last resort when the situation calls for it.

If you are interested in learning the use of a katana or any other bladed weapon, it is crucial to receive proper training from qualified instructors who can teach you the appropriate techniques, safety protocols, and the strengths and limitations of the weapon.

As always, safety and responsible use of any weapon should be paramount, and adherence to local laws and regulations is essential.