[mjgoins]

It's worth pointing out that no one ever finishes (ascends) a game of Nethack without looking at the spoilers, so they're really not spoilers, they're more like the instruction manual.

It is definitely more fun to try playing the game for several hours without reading the spoilers, but you're not going to figure out stuff like the Invocation Ritual without reading the spoilers.

[schoen]

There is at least one self-described unspoiled ascension, in 2010:

https://groups.google.com/forum/#!topic/rec.games.roguelike....

This did involve use of wizard mode (not for the unspoiled ascension itself, but beforehand for learning stuff).

People often ask how someone would learn how to perform the Invocation without spoilers. One intended answer by the DevTeam is to pay the Oracle for a series of major consultations, one of which (somewhat elliptically) explains the Invocation. The Oracle consultations aren't considered spoilers if you pay for them in-game.

[ijk]

Technically, the Oracle is supposed to dispense enough information to figure out most of the important stuff.

Of course, you'd have to be good enough at the game to survive to the Oracle and have the cash to pay for the major consultations. And you'd have to know that information source exists.

Since Nethack is a game where not knowing the details of some minor edge case can and will kill you dead, or deader than dead, I don't know of anyone who actually relied on that (though there may very well be someone).

[acheron]

Well, the Oracle will tell you about the Invocation Ritual.

What's you're not going to figure out spoiler-free are things like magic cancellation. Which is maybe not literally essential to winning, but you're going to have a tough time without it.