Dan, so many people ask that and it seems to start arguments but almost everyone seems to agree that heavy is better and somewhere between 9 and 12" is somewhat easier to throw. Some folks on here like all custom stuff, some others factory made but all seem to agree on the above. Personally, I use some Cold Steel, some Condor and a variety of heavy handmade blades. All work fine. This is particularly true if you make every effort not to throw one against the other when practicing. Carbon steel fares much better than stainless when they hit anything hard.