Fenriz has said that the band began writing this album in late 1991 with the intention of making a pure black metal record, and that they used the studio to arrive at a sound that was colder and grimmer than the one before it. Bands say things like that all the time and almost none of them deliver. This one delivered so completely that the result has been used as the definition of the form ever since, and it is still, thirty three years later, the best album the genre has produced.
It is also the one that loses every poll. There is a reason for that and the reason is not musical. The shelf it belongs at the top of, with the years, the labels and the studios, is the album list.
What they were walking away from

Darkthrone in 1991 were a technical death metal band from Kolbotn, a commuter town at the southern end of the Oslo line, signed to an English label and heading somewhere. Soulside Journey came out that February. Ten months later they had abandoned all of it, and A Blaze in the Northern Sky, recorded in August 1991 and released on 26 February 1992 after Peaceville tried to stop it, is the sound of a band throwing a career overboard in real time. Half of that record is still death metal. It is a transition, audible as a transition.
What arrived a year later has nothing left over. Under a Funeral Moon was recorded in June 1992 at Creative Studios in Kolbotn with an engineer credited only as Vidar, and Peaceville released it on 15 February 1993. Fenriz played drums and wrote the words, Nocturno Culto played bass and sang, Zephyrous played lead guitar, and it was the last album the three of them made together. Forty minutes and thirty seven seconds, eight songs, and no residue of anything the band had been before.
The one production idea, and what it does
The technical decision that separates this album from every other record of the period is that the distortion is not confined to the guitars. It is smeared across the whole mix, drums included, so the album does not sound like instruments being recorded in a room; it sounds like a single degraded object with music happening somewhere inside it. Everything is treated the same way and nothing is given room to breathe, and that is why the record has an atmosphere the two either side of it do not quite reach.
No light, but rather darkness visible.
John Milton, Paradise Lost
What that buys is a specific kind of cold. The famous album that followed got its cold from tape hiss and a bedroom; this one got it in a working studio, on purpose, with an engineer present, which is the harder and more repeatable achievement. Nothing here depends on an accident, and nothing here needs an anecdote to explain why it sounds the way it does.
The songs, which is the part that settles it

Eight tracks, none of them padding, and the pacing varies in a way that nothing else in the second wave manages. "Natassja in Eternal Sleep" opens at three and a half minutes and moves. "Summer of the Diabolical Holocaust" and "The Dance of Eternal Shadows" hold the middle tempo where this band always did their best writing. "Unholy Black Metal" is three and a half minutes and functions as a statement of position, which the band clearly intended and which has been quoted back at them ever since. "To Walk the Infernal Fields" runs seven minutes and fifty seconds and is the most ambitious piece of construction on any Darkthrone album.
This one got its cold in a working studio, on purpose, with an engineer present, which is the harder and more repeatable achievement.
Then the title track, then "Inn i de dype skogers favn", the one song here in Norwegian, and then "Crossing the Triangle of Flames" at six minutes to close. Zephyrous's lead playing is the element that disappeared from the band afterwards and it is more important than its reputation suggests: it is what keeps the middle of the album from flattening out. He was gone within a year and the next record was made by two people.
Where the sound came from
None of this was invented in Kolbotn, and the band have never pretended otherwise. Bathory recorded Under the Sign of the Black Mark at Heavenshore Studio in Stockholm in September 1986 and it was released on 11 May 1987, one man playing almost everything, and Fenriz has called it the quintessential black metal album. The proportions on that record are the proportions here: guitar as a single sheet of treble, vocals set back in the reverb, drums keeping time and taking up no space. What the Norwegians added five years later was a doctrine about how far the removal could be pushed, and the willingness to lose a record deal over it.
The other inheritance is from Switzerland. The mid tempo, the weight of the chord changes and the sense of ceremony in the slower passages here come out of the first two Celtic Frost records rather than out of anything Scandinavian, and Fenriz has cited Morbid Tales among his sources for the album that followed this one. Hearing those two lineages sitting inside the same forty minutes is the most useful thing an attentive listener can do with this record. It is not a rejection of everything before it. It is a very precise selection from it.
Why it loses the vote
Take the three albums apart and the ranking is not close. The first is a transitional record with half a death metal band still inside it. The third is the purest statement of a theory and has two thin songs on it. This one has the best writing, the widest range of tempo, a real lead guitarist and the same production argument made without needing the argument explained. It should win every time, and it does not win at all.
The reason is that it has no story attached. There is no bedroom, no four track machine, no slogan on the back cover, nothing for a writer to open a paragraph with. It was made in a studio, by three men, in a normal way, and it is merely better. An album that arrives with a scene attached will always be easier to write about than one that does not, and easier to write about has been mistaken for better for thirty years.
The verdict
If you are starting with this genre, start here rather than with the album everybody names. It is the shortest route to understanding what the whole style was trying to be: cold without being thin, repetitive without being static, extreme without any of the theatre that dates so badly on records of this period. Play it loudly and on speakers, because the mix was built for a room.
What it is not is a concept album, and the difference matters more in this genre than in most, because the form's other great strain of ambition runs through records built around a single idea or narrative from the first note to the last. That tradition, from the Norse cycles to the theological ones, is black Metal Concept Albums.