In answer to u/lonelittlejerry's question: What's the most thorough example of a communist revolution? That is, one that changed a society in a long-lasting, permanent way

My answer:

There's a common trope from socialist circles that goes like this: "Marx's plans would work, it's just that communist states didn't follow them properly."

Yet that trope doesn't stand up to scrutiny.

If you mean Karl Marx's theories followed as closely as possible by an authoritative government, then you could judge each communist country by his 10 point plan laid out in his 1848 Communist Manifesto.

Marx's 10-point plan:

1. Abolition of property in land and application of all rents of land to public purposes.
2. A heavy progressive or graduated income tax.
3. Abolition of all rights of inheritance.
4. Confiscation of the property of all emigrants and rebels.
5. Centralisation of credit in the hands of the state, by means of a national bank with State capital and an exclusive monopoly.
6. Centralisation of the means of communication and transport in the hands of the State.
7. Extension of factories and instruments of production owned by the State; the bringing into cultivation of waste-lands, and the improvement of the soil generally in accordance with a common plan.
8. Equal liability of all to work. Establishment of industrial armies, especially for agriculture.
9. Combination of agriculture with manufacturing industries; gradual abolition of all the distinction between town and country by a more equable distribution of the populace over the country.
10. Free education for all children in public schools. Abolition of children’s factory labour in its present form. Combination of education with industrial production

As Marx's plan alludes to, no country of any size, communist or otherwise, starts off as a blank slate. To follow out Marx's ideas, you need to upset the existing order - and may face headwinds like the Soviet Union did - like the German invasion just two decades into its existence.

As a communist, you have to take the state as it is. And in the case of the Bolsheviks, they inherited a state in a pretty poor condition, had to fight rival forces and peasant resistance during the Civil War - and then had to wait a decade and regroup before having the strength to fulfil the plan.

Hence, to fulfil Marx's plan, the job fell to Stalin. This plan in practice was collectivization and industrialisation.

Prior to the plan, the Soviet Union was under Lenin's New Economic Policy, or NEP. The NEP essentially meant that capitalism was brought back for most of the 1920s as a means to quickly stimulate a shattered post-civil war economy.

Of course, capitalism is anathema to Marx's teachings- which means that the Soviet Union can only be considered a true Marxist state when Stalin ended the NEP in 1928 - and commenced collectivisation and industrialisation that would transform the Soviet Union into what it's best thought of as: a industrialised, almost fully state-owned economy.

Arguments

Communist leaders long had arguments and discussions as to who was the most orthodox Marxist - so it's hard to say what is the most thorough example of a Communist revolution.

Note that many Communist leaders, like China's Mao and Albania's Hoxha, also blended nationalism with their communism - as in inevitable when you're from a country that you rule. However, only one country changed its name to reflect its political, not geographic status: the Soviet Union. The implication of the name change was that any country could join the Soviet Union.

A cursory evaluation of the Soviet Union's adherence to all the points above gives them a pretty high score. First under Lenin, and then completed under Stalin, the Soviets carried out nearly of all of Marx's points - with a few noteworthy differences.

One notable point where the Soviet Union deviated was point 2: a heavy progressive or graduated income tax.

As the Bolshevik party understood from quite early on (much to the disappointment of the most orthodox Marxists), if you want skilled labour - and people wanting to upskill - you have to motivate them by paying them more. This would have thus made higher taxes on higher earners self-defeating.

Here's a few more points of deviation and failure in the second parts of the points that the Soviet Union failed to successfully carry out:

7: "...the bringing into cultivation of waste-lands, and the improvement of the soil generally in accordance with a common plan."

This was certainly tried. Russia is not short of 'waste-lands'. Yet as Nikita Khrushchev's virgin lands campaigns proved, which involved trying more farming in Siberia and Kazakhstan, sometimes it's easier just to make the most of the quality farmland you do have (such as in Ukraine). There is a point here where science clashes with ideology.

8: "Establishment of industrial armies, especially for agriculture."

Certainly, the Soviet Union was pretty good at employment - the state doctrine being that work was essential to all but a few exceptions (the very old, very young and disabled, mainly). Trotsky was certainly an advocate for labour armies - although in practice these 'armies' were mostly in the form of gulag prisoners or German convicts from WW2. It goes without saying that productivity was lower for these cohorts of the workforce - although they were useful for doing work that no-one else wanted to do.

9: "...gradual abolition of all the distinction between town and country by a more equable distribution of the populace over the country."

The Soviet Union certainly saw a more equable distribution of the populace over the country. Entire cities like the Reddit-famous Norilsk were built on permafrost, to extract rare minerals and metals. Workers who moved to these cities received higher salaries to compensate for the harsher climates. A lasting impact of the Soviet Union was the enormous population shifts from the country to the cities, which fuelled industrialisation. Side note: curiously, America's and Russia's country-to-city population shifts in the same time period mirror each other fairly closely.

However, just as in Tsarist times and modern Russia, the distinction between town and country in the Soviet Union was enormous - and this was either by design or necessity, given the Soviet viewpoint that cities are for factories, and the country is for agriculture. Also, given the Soviet Union's geography, certain areas like Moscow and Leningrad (now called St Petersburg) are less suited for agriculture than say Ukraine - which makes an urban/rural divide a practical measure.

To best demonstrate the enormous Soviet divide: from the earliest years of the Soviet Union, for Soviet bureaucrats, having to leave the power centres of Moscow or Leningrad was essentially internal exile. Witness how Stalin demoted hero WW2 general Zhukov to the Odessa military district, and Khrushchev punished disloyal members of the party in the 1950s: sending former top diplomat Molotov as ambassador to Mongolia, and making Malenkov (once Stalin's successor) director of a hydroelectric plant in Kazakhstan.

Conclusion:

With the exception of the post-script points, the Soviet Union could lay claim (among rivals) for being the most orthodox Marxist state. It fulfilled the vast majority of Marx' 10-point plan - although like all plans, the devil was in the details.

Suggested sources:

An Economic History of the U.S.S.R. – 28 Jun. 1990 , by Alec Nove

The Rise and Fall of the The Soviet Economy- An Economic History of the USSR 1945 - 1991, by Philip Hanson

Communist Manifesto, Chapter II, 1848, by Karl Marx

Stalin: Waiting for Hitler, 1929–1941, by Stephen Kotkin