Tai Chi swords, also known as taijijian, are often designed with a flexible blade as a characteristic feature. The flexibility of Tai Chi swords serves several purposes:

1. Martial Application: Tai Chi is a martial art that emphasizes softness, flow, and precision in movements. The flexible blade of a Tai Chi sword allows for the absorption and redirection of force during combat. The sword can bend or flex upon impact, dispersing the energy and reducing the risk of the blade breaking or damaging the opponent's weapon.
2. Training and Sensitivity: The flexible blade promotes training in sensitivity and awareness. It requires the practitioner to develop a refined sense of touch and control to maintain proper alignment and manipulate the sword effectively. The flexibility of the blade helps the practitioner develop a deeper understanding of the principles of Tai Chi, such as balance, relaxation, and energy flow.
3. Flowing Movement: Tai Chi forms and techniques are characterized by flowing and continuous movements. The flexible blade enhances the fluidity of these movements, allowing the sword to move smoothly and effortlessly through various transitions and techniques. The flexibility complements the principles of Tai Chi, promoting harmonious and interconnected movements.
4. Safety and Practice: The flexible blade reduces the risk of injury during practice and training. It minimizes the impact force and lessens the likelihood of accidental injuries caused by a rigid blade. This makes Tai Chi swords with flexible blades safer for solo practice, partner exercises, and demonstrations.

It's worth noting that not all Tai Chi swords have flexible blades. Some practitioners may choose swords with varying degrees of flexibility based on personal preference or the specific style they follow. The flexibility of the blade is often considered an important characteristic in Tai Chi sword practice, as it aligns with the principles and objectives of the art.