Subdermal transmitter using vibrations. Embedded BoneContact Auditory communication. No end of ways to cheat without being detected if all you need is an inbo

Subdermal transmitter using vibrations. Embedded BoneContact Auditory communication. No end of ways to cheat without being detected if all you need is an inbound signal (The games were being broadcast on the internet). It's only a little bit harder if you need to communicate in two direction, but - this is chess - you don't need to communicate much data to send out position updates.