Shogun's chin and BJ Penn's skin is something that Sherdog posters often overlook because they are too engrossed talking shit about Jones' long arms. Chin, as far as we know, is natural and there is no scientifically proven way to drastically improve it. Some people are born with natural good chins, some with weak ones and one's chin is often an important factor in determining one's career as a fighter. Shogun Rua is obviously blessed with a great chin as we can see from the Henderson fight and I believe he is abusing this unfair advantage too much in his fights. Just look at the way he took those shots with his iron chin! Having tough skin is also beneficial in a MMA fight. It reduces a fighter's chance of losing via cuts, skews the judge's opinion to some extent and helps to boost a fighter's confidence. BJ Penn is the rare few that is known for having leather skin. He seldom bleeds even though he had taken many beatings in his career and I believe he has been abusing them for his whole career, especially towards the end where he started getting hit much more. See how fresh his face looked even after a five round war with Uno? In addition, there is no disadvantage to having a strong chin and leather skin. Long arms, on the other hand, reduces the mass of muscle which a fighter can carry, makes the fighter more susceptible to arm locks and requires agility and a good game plan to be used well. Ok that's it from me.