A proclamation was issued (known as the Voroshilov Order, after the then head of the armed forces), which required all those aged 18 to join up with the army.
It wasn't the name I expected, the 1939 Law of Universal Conscription or a similar formulation. It turns out that Kliment Voroshilov gave a bombastic speech to the Supreme Soviet on 31st August 1939. It can be viewed here.
The actual law was passed on 1st September 1939, it can be found here. Note that that was signed by M.I. Kalinin and A. Gorkin on behalf of the Supreme Soviet. It goes without saying that not every eighteen year old would necessarily have gone into the army. This proclamation was to do with the building up of a reserve.
The key point was that conscription was lowered to eighteen years, having, apparently only recently been reduced from twenty-one to nineteen (Lieutenant-Colonel Albert Seaton,
… Pre-war Soviet theory estimated that the army would have to be completely replaced every four to six months during heavy combat. To satisfy this need, the 1938 Universal Military Service Law extended the reserve service obligation to age 50 …
Note the assumption of an absolutely horrifying rate of loss. The obligation to join the military was also included in article 132 of the Soviet constitution of 1936 (the Stalin Constitution).
On the same page Glantz adds:
By the time of the German invasion, the Soviet Union had a pool of at least 14 million men with at least basic military training.
On 22nd June 1941, the day on which the Nazis attacked, there were roughly five million men in the Red Army (The late Professor John Erickson in The Road to Stalingrad, ISBN 0 297 76877 8, page 225, gave a figure of 4.7 millions).
It is likely that many in Averbakh's circle, as well as others, referred to the 1939 law as the Voroshilov Order. It's not a name, as a Westerner, that I'm used to. However, Voroshilov was promoted as a great military hero, so listeners to his speech would automatically associate him with the order. In the English version, a note explaining this would have been useful, although I can't blame a translator of chess books for not doing so: one can't know everything.
Kliment Voroshilov is someone I can expatiate on with confidence. Doubts about his competence go all the way back to the Russian Civil War.
Born in the Ukraine in 1881, the son of a railway worker, Kliment Yefremovich Voroshilov joined the Bolshevik faction after the 1903 split in the Russian Social Democratic Party. A participant in both the 1905 and 1917 revolutions, he was one of the first recruits to the Cheka, which was established by Feliks Dzerzhinsky (1877-1926) during the Russian Civil War. In 1918 he was chosen by Stalin as the military specialist commander of the Tsaritsyn (modern day Volgagrad, but better known as Stalingrad) front even though he had no experience or knowledge of military affairs: it was the making of his career. Upon arrival, he had many dedicated military professionals arrested or sent back to Moscow on the charge that they were counterrevolutionaries.
His arrival did nothing for military efficiency. In Trotsky's opinion large numbers of troops were needlessly tied up at Tsaritsyn, thereby enabling Stalin to invent the myth of a heroic defence. Stalin went on to clash with Trotsky and Tukhachevsky (1893-1937) over the conduct of the war with Poland that broke out in 1920, Voroshilov was in Stalin's camp. As a loyal supporter of the future dictator, Voroshilov was promoted repeatedly and lauded as a military genius. In late 1925 he replaced Mikhail Frunze as People's Commissar of Military and Naval Affairs, a marker as to who was the most powerful man in the Soviet Union. Voroshilov held this position (the title later changed to Commissar of Defence) until 1940. He was notorious amongst those who knew him for having no head for detail. Despite being blamed by many for the Soviet debacles in the Winter War with Finland (1939-1940), Voroshilov was not purged, merely sidelined. No longer Commissar of Defence, he was appointed the deputy chairman of the Defence Committee. Following the disasters on the frontiers after Hitler attacked the Soviet Union on 22nd June 1941, Voroshilov, to the great cost of many, was appointed glavkom (commander-in-chief) of the fronts to the north-west (10th July 1941). Out of his depth, Leningrad was cut-off, save for a route over Lake Ladoga, and appeared on the verge of falling. Fortunately for the defenders, he was superseded, although he continued to hold senior positions throughout the war.
Early in the 1950s, the paranoid Stalin began to entertain doubts as to Voroshilov's loyalty, the dictator wondered whether his underling was an English spy. Happily for Voroshilov, Stalin died in 1953. Voroshilov was appointed Chairman of the Presidium of the Supreme Soviet (1953-1960). A long time member of the Politburo, he was denounced by Khrushchev in 1961 and stripped of his posts. He died in 1969.
For most of the Stalin period Voroshilov was promoted as a great military leader, towns were named after him and the heavy KV tanks (not as famous as the T34 medium tanks, but also an unpleasant shock to the invading Nazis) also bore his name. An irony is that Voroshilov was opposed to the expansion of the armoured forces (see Erickson op. cit., page 32). Not hated in the manner that Mekhlis was, many Red Army officers nonetheless held a low opinion of Voroshilov personally, they felt he could have done more to protect the officer corps before it was shattered (tens of thousands were shot or sentenced to the Gulag) by the dictator.
On page 43, Averbakh recalls that he was sent to Naro-Fominsk, where he spent twelve hours a day building BT tanks (almost certainly BT-7s, the BTs performed well in the 1939 battle of Khalkhin Gol, which put a halt to Japanese ambitions at the expense of the Soviets; but, as Averbakh relates, were of little use when fighting the Nazis). The town is about forty miles south-west of the centre of Moscow (it's more or less on a straight line drawn from Moscow to Kaluga, where Averbakh was born). Averbakh relates that he was sent back to Moscow in September 1941 when the Nazis advanced closer to Moscow. Bock, the commander of the Nazi Army Group Centre, issued the directive for Operation Typhoon, which was supposed to result in the capture of Moscow, on 16th September. Thus Averbakh probably returned in the latter half of that month. It is probably worth noting that Naro-Fominsk was the site of one of the first morale boosting Soviet successes against the Nazis (along with Tikhvin, which helped save Leningrad). Glantz (op. cit.) on page 168 gives:
… the XX Army Corps' 258th and 292nd Infantry and 3rd Motorised divisions north of Naro-Fominsk, and the 183rd Infantry and 20th Panzer divisions and one regiment of the 15th Infantry south of Naro-Fominsk. All three attacked … on 1st December, but the attack had only limited armoured support and ran directly into a carefully prepared Soviet anti-tank region … To the south, the systematic defence by Colonel V.I. Polosukhin's 1st Guards Motorised Rifle division at Naro-Fominsk became a legend of tenacity.
Also on page 43, the words: Once the bombing started and More than once, I … put the out the fires started by the incendiary bombs … appear to have been misunderstood by some readers. The pro-Nazi Paul Carell (aka Paul Karl Schmidt, he was an SS obersturmbannführer responsible for propaganda during the war) in his book Hitler's War on Russia (published by Harrap and Son in 1964) has this to say on page 193:
Anyone remembering the wartime enemy raids on German towns will ask: What about the Luftwaffe? He will note with surprise that the German Luftwaffe did not succeed in interfering with the passage of Soviet troops to the front through the Moscow transport network, nor in preventing the arrival of Siberian divisions, nor generally in paralysing Moscow itself as an area immediately behind the lines. Nothing of that kind happened. The last German air raid on Moscow was made during the night of 24th/25th October with eight machines. After that, only nuisance raids were made in December… Why?
Every German airman who was at Moscow knows the answer. The Russians had established tremendously strong anti-aircraft defences around the city. The forests were thick with AA batteries. Moreover, the German Luftwaffe in the east had been decimated in ceaseless operations, just as much as the armed forces, and had to yield the air to the Soviet Air Force, which, before Moscow, was numerically twice as strong. Besides, the Soviet Air Force had numerous well-equipped airfields near the front, with heated hangars, enabling any unit to take off swiftly and repeatedly, regardless of the weather. The Germans machines, by way of contrast, were based on primitive airstrips, a long way behind the fighting line, which permitted operations only in favourable weather. Moscow was virtually spared from the air.
I am sure that grandmaster Yuri Lvovich Averbakh, unlike his detractors, is well aware of this. It is not all that difficult to imagine that living in cramped conditions in an attic, and getting bombed to an accompaniment of tremendously strong anti-aircraft fire (Soviet anti-aircraft equipment was very good) was a vivid experience. There is no need to read more into it than the facts warrant.
Note, too, that Moscow was never under siege, although the Nazis got very close. The scholar David Stahel, in his book Kiev 1941 (ISBN 978-1-107-01459-6), has this to say on page 386 about the sieges and near sieges in the opening months of Barbarossa (note that not all of these were cities):
The Soviet naval base of Hanko on the southern coast of Finland was blockaded by mines and defended by almost 20,000 Soviet troops along the narrow peninsular linking it to the mainland. It was only evacuated early in December 1941. Across the Gulf of Finland the siege of Tallin lasted from mid-July until 28 August and ended with the capture of 20,000 Soviet POWs. The monumental siege of Leningrad was only getting underway in early September. Further south the siege of the Soviet fortress of Brest lasted from the first day of the war until the last few defenders were killed in late July. Mogilev on the Dnepr was the site of another desperate siege in July,… Kiev was also under siege from the second week of July …
It's true, though, that David Glantz (op. cit., page 148) wrote: In essence, Moscow was under a state of siege. He was describing the rushed construction of additional defences in October on the immediate approaches to Moscow and in the city itself. Six thousand NKVD (i.e. Chekist) troops, supplemented by militia units, blocker detachments and so forth were responsible for security and the construction of defences. Four hundred thousand inhabitants of Moscow and its oblast (province) were pressed into service to construct these defences. They did so over twenty days. There was real panic in Moscow, as discussed by Averbakh on page 44. Nonetheless, this was not a siege as commonly understood.