Why is the Fried Liver attack regarded as "easy to refute"
It has been known for some 400 years that Black should not play 5. ... Nxd5 or they are in trouble. The most common of the better replies is 5. ... Na5, which hits the bishop, the usual continuation being 6. Bb5+ c6 7. dxc6 bxc6. The other options are 5. ... b5 and 5. ... Nd4. Any of the refutations may not be easy to find if you see the attack for the first time, but anyone playing the Two Knights Defense should learn it soon.