A bokken and a katana are two distinct types of Japanese swords with key differences in their construction, purpose, and usage. Here's a breakdown of their differences:

1. Construction: A bokken is a wooden sword, typically made from a single piece of hardwood like oak or hickory. It is solid and does not have a blade edge or a sharp point. In contrast, a katana is a traditional Japanese sword made of steel, with a curved blade, a sharp cutting edge, and a pointy tip.
2. Purpose: Bokken is primarily used as a training tool in martial arts such as kendo, aikido, and kenjutsu. It allows practitioners to practice sword techniques and sparring safely without the risks associated with using a sharp metal sword. On the other hand, the katana is a functional weapon historically used by samurai warriors in Japan. It was designed for cutting, slashing, and thrusting in combat.
3. Weight and Balance: Bokken tends to be slightly heavier than a katana due to its solid wooden construction. The weight and balance of a bokken are intended to mimic that of a real sword, allowing practitioners to develop strength, technique, and muscle memory. A katana, being a steel weapon, has its own weight distribution and balance specific to its design.
4. Blade Shape: Bokken typically has a straight blade without a curve, reflecting its wooden construction. On the other hand, the katana features a distinctive curved blade, designed to optimize cutting and slicing motions, as well as enhance balance and maneuverability.

In summary, a bokken is a wooden training sword primarily used for martial arts practice, while a katana is a functional steel sword traditionally used in combat. The bokken provides a safe and effective way to learn sword techniques, while the katana is a historical weapon with a specific design for practical use in warfare.