a certain nonchalance, so as to conceal all art and make whatever one does or says appear to be without effort and almost without any thought about it
Might this nonchalance be useful or even essential for a referee? The "without effort" part resonates, if the depiction and enactment of the world is "with effort", the flow might stop.
Sprezzatura was coined by Baldassare Castiglione in his 1528 The Book of the Courtier. Dissimulation of art combines with simulation of nature. The ways of the courtier must never appear as the product of effort or work. Sprezzatura implies a sort of indifference to what is done, an effort to hide the effort, an ostentatious art-dissimulating nature-likeness.
What Prince is there to please? The court is the table hosting our games and the courtier under scrutiny is the referee. The game master has to show some maestria.
The Book of the Courtier is set in the court at Urbino. It was not the court of a super power in the Italian Peninsula, but it shone nonetheless. Outside of the wall of the palace, Italia was ravaged by French and Spanish armies and the various mercenaries lured in. The Urbino court was a preserved garden and the courtiers were hard at work keeping the merriment flowing. Worldly matters were for lowly civil servants like Macchiavel, in Firenze, on the other side of the Apennine mountains.
The courtier-referee can't really hide their prep, but they can artfully divert the attention of the Prince from it and focus the audience on the shared illusion.
Let's leave our referee-courtier fall short here and meet our second Balthazar. He is a Spanish writer, philosopher, and jesuit, named Baltasar Gracián. He wrote six books, with titles translated to English as, for example, The Hero, The Complete Gentleman, The Art of Worldly Wisdom, and The Critic.
Gracián was a successor to Castiglione, his writings built on the Italian courtier concept, but the Spanish court was not that of a small principality, it was a court spanning Europe and America, its world festered with malice, cruelty, and falsity. Artifice, cunning, and deception were indispensible. The Gracián courtier is a solitary knight fighting against everyone.
Our soldier of Jesus describes for his courtier a progression in three levels, rather epochs. The first part is dedicated to studies, where one is in dialog with the dead (authors). The third part is dedicated to reflection, the dialog with oneself. The second part of the courtier life is where action takes place. Gracián puts emphasis on Discretion, a kind of practical intelligence, acknowledging that the rules vary according to context.
Not enough magic in this post? Let's meet our third, original, Balthazar. The third of the Magi. He was supposed to be a Babylonian scholar.
Not enough table-top role-playing in this post? Watch this video which presents the courtly Ariosto Furioso role-playing system.
Sprezzatura, "A fundamental know-how to perform with skill under every circumstance".