This is the icon for the Freeware SGF Editor (Moyo Go Studio's icon looks the same, but is red).
It was non-trivial to get this freeware SGF Reader/Editor released: I had to get the download size as small as possible - I even tried to NOP out unused parts of a DLL so that it would compress better! That involved interactive disassembly and tracing function calls. My little scheme didn't work because that DLL is loaded by another DLL which does a checksum verification..