Pietro Carrera’s advice
In his early 17th century book, Il Gioco degli Scacchi (The Game of Chess), Pietro Carrera - the father of the Sicilian defence - offers advice on how to prepare for a chess match that I thought might be good advice for traders as well:
You must abstain some days from meat to clear your brain, and also let blood. You should take purgatives and emetics to drive away the humours, and must above all be sure to confess your sins and receive spiritual absolution just before sitting down to play in order to counteract the demoniacal influence of magic spells.
