9th Dan Uechi Ryu master Kiyohide Shinjo training with Sanchin jars.

Okinawan karate has several training techniques that are designed to strengthen and condition the body using simple everyday objects. Sanchin are heavy jars that are gripped with the fingertips. Makiwara is a striking post the top of which is often wrapped in leather or straw. It is similar to a boxers punching bag, but with a smaller target.

10th Dan Shorin-ryu Karate Master Sokuichi Gibu training with makiwara

In the photo below Gaja-sensei demonstrated how a simple bucket of stones was used for fingertip conditioning. He thrust his hand in so hard and fast, the force sent some stones flying out of the bucket.

Uechiryu Karate 9th dan Takehiro Gaja – Fingertip Conditioning

Here’s a short clip showing a few different techniques by various masters including Kiyohide Shinjo.