A tanto is a traditional Japanese dagger characterized by specific design elements that distinguish it from other blades. Here are the key features that make a blade a tanto:

1. Blade Length and Shape: A tanto typically has a blade length between 15 and 30 centimeters (6 to 12 inches). The blade is generally straight or may have a slight curve near the tip. Unlike the longer swords such as the katana or wakizashi, the tanto is a shorter blade designed for close-quarters combat.
2. Pointed Tip: The tip of a tanto blade is sharp and symmetrical, often forming a triangular or straight shape. This design maximizes the stabbing and penetration ability of the blade.
3. Single or Double Edged: Tanto blades can be either single-edged or double-edged. Single-edged tantos have a primary cutting edge on one side while the backside may be unsharpened or feature a secondary bevel. Double-edged tantos have sharpened edges on both sides, extending to the tip.
4. Minimal Tapering: Tanto blades typically have a minimal taper from the base to the tip compared to other Japanese blades. This design contributes to their strength, durability, and ability to withstand heavy-duty tasks.
5. Sturdy Construction: Tanto blades are known for their robust construction. The spine (mune) of the blade is often thicker compared to other Japanese swords, enhancing their durability and resistance to bending or breaking.
6. Utility and Martial Arts Applications: Tantos were historically used as utility knives for various everyday tasks. They also served as effective self-defense weapons for close-quarters combat. Today, tanto blades are still appreciated for their utility, combat applications, and aesthetic value.

These defining characteristics collectively distinguish the tanto as a distinct type of blade within the realm of Japanese swords and daggers.