What do you do if someone attacks you with a knife? It's a question that came up while some Moy Tung Ving Tsun students were teaching a self defense class to a dozen or so parents and teachers (all women) at a daycare center in a rough part of Brooklyn. ...

It’s an oft-quoted truism in books on learning and productivity that it takes 10,000 hours to achieve true mastery in any skill, from composing symphonies to playing tennis.