"At that age (ten), the odd piece here or there often makes little difference. Rather, ingenuity and the will to win may prove decisive."
"In the eighteenth century they announced their first rule: "Sortez les pieces" - "Get the pieces out". "It took a hundred years before a new rule was announced. Anderssen, the winner of the first International Tournament, that of London, 1851, said:
"Move that one of your pieces, which is in the worst plight, unless you can satisfy yourself that you can derive immediate advantage by an attack"
"A few decades went by [...] the masters evolved a "public opinion":
LASKER, Manual of Chess (second book)