Inner Ring Grindedit this page

From YoYo Wiki

Also known as Inner Rim Grind , Thumb Grind or IRG.

The Inner Ring Grind is a grind trick in which something (typically your thumb) is placed inside the ring of one half of a yo-yo while spinning, thus grinding on the object. These are not possible with all yo-yos due to sidecaps or lack of a groove.

These tricks were popularised by Andre Boulay in his video "Dark Magic" although they had been done before. They are often referred to as "thumb grinds" although although the term "thumb grind" could also refer to when the whole yo-yo grinds sideways with the pog on top of your thumb.

[edit] Performing an Inner Rim Grind

First off you want to have a yo-yo with a nice size inner edge where you can put your thumb in. You can see this simply by taking the cap off of your yo-yo with a suction cup or looking on the inside of the yo-yo. Now lets start. Ok throw a trapeze make it so its not far away from your thumb, now take your middle finger and bring it together or bring your non throwhand hand together, now stick your thumb in the gap from the yo yo, heres a tip bring your thumb with the yo yo up not to get it stuck on the string. OK you did it. But the yo yo is going to start revolving as soon as it touches your thumb.