Introduction to the Golf Clubs Acquired in Japan: Yamaha PROTO FORGED FLEXY

 

The clubs you have are the "PROTO FORGED FLEXY" model from Yamaha (YAMAHA).

These irons appear to have the following characteristics:

• Manufacturer and Model Name: YAMAHA PROTO FORGED FLEXY

• Construction: The clubs are marked as FORGED (soft iron forging). Generally, soft iron forged irons are known for a soft feel at impact (though the feel of this specific model can vary depending on its age and individual club characteristics).

• Shaft: The photos show a graphite shaft labeled "YAMAHA SENSUS". Different numbers (e.g., 7126 M, 7027 M) are visible across multiple iron numbers. This suggests that the shaft properties—such as weight, torque, and kick point—may have been tuned specifically for each iron number within the set.

• Iron Numbers/Design: The back of the head (the cavity) features an engraved value called the "CAVITY RATIO," which varies among the photographed clubs, showing distinct percentages like 44%, 46%, 50%, 56%, 59%, and 62%. While the precise meaning of this "CAVITY RATIO" is unclear, it likely indicates a design where the cavity depth, shape, and center of gravity (CG) are altered for each iron number (e.g., from 3-iron to pitching wedge) to optimize performance (such as ease of use and distance) for that specific club. It's a common design principle for long irons (lower numbers) to prioritize forgiveness, while short irons (higher numbers) are designed for greater workability.

Given that these are relatively older, soft-forged irons, it is probable that they were originally designed for intermediate to advanced golfers of that era.