This is because one of the strings has actually cut into the other to created a "notch" (so to speak) eg partial cut thru. When this occurs, it is a sign your string will need to be replace in the very near future.
"Notching" is extremely common to certain brand and models - Yonex BG66 is probably the most well known of the lot. It even happens if you had the racquet restrung and left it unuse for a while! Someone I know was skeptical and did the above test ... he was disappointed to find the notch after leaving the newly strung racquet unuse for a few weeks!
The effect is most noticable on darker coloured strings - see the enclosed pix from one of my own racquet below. The notches are the white areas on the black string - after I moved the now stationary cross-string aside for the photograph.
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| Effects of "notching"on the strings |
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| Close-up of the "notching(s)" |
Even so, Yonex BG66 remains a popular choice for many players ... hence good profits since it has to be replaced often!
