In 1929-1933 the biggest in history of capitalism crisis broke out. Industrial production volume decreased by 38% in average, in agriculture by one third, in world trade - by two thirds.
In Germany Adolf Hitler's National-Socialist Party comes to power on the wave of crisis. In the East Japan activises its actions with the purpose of broadening international sphere of influence. Different variants of "tough" regimes are set up in a number of European countries: in Italy, Spain, Hungary.
In extremely tense international atmosphere of the late 20-s and 30-s the USSR passed three main stages:
1) 1928-1933. In Europe the USSR has allied relations with Germany, opposition to "democratic" countries; in the East - advancing to China and activation in Afghanistan and Iran.
2) 1933-1939. Approximation with Great Britain, France and the USA on anti-German and anti-Japan bases, willingness to maintain spheres of influence in the East and avoid direct confrontation with Japan.
3) 1939- 1941. Approximation with Germany and Japan.
When on the first and second stages the Soviet Union faced relatively stable situation on the western borders and didn't take any steps, capable to change the status-quo, the situation in the East was different. On the Far East hostilities were in progress (in which the Soviet Union was taking part), and the current political map of the world was changing. The most significant events were the following: Soviet-Chinese armed conflict on Chinese-Western railroad in 1929; Japanese aggression in China (1931-1932).
The beginning of Japanese aggression to China in September, 1931 and in March, 1932 facilitated improvement of Soviet-Chinese relations.
In July of 1937 Japan began a large-scale military operation against China. As a result of two year hostilities Japanese Army occupied chief industrial and agricultural regions of China. Worsening of situation in Chinese Republic strengthened its contacts with the USSR. In August of 1937 the USSR and China signed an agreement about mutual non-offence. Right after the signing the agreement the Soviet Union carried out mass military technique deliveries to China, which helped the latter to restrain the offence of Japanese Army.
1928-1933 was a period of very unstable relations "USSR-England, USSR-France and USSR-USA. In October 1929 diplomatic relations USSR-England, that had been broken up in May, 1927, were restored.
In 1930-1931 Soviet-France relationship became very tense.
French government accused Soviet Russia in interfering into its internal affairs. In 1932 a mutual non-offence agreement was signed between Soviet Russia and France.
In 1932 agreements about mutual non-offence with the USSR signed Finland, Latvia, Estonia. These nations were in the fairway of relations with France and the above mentioned agreements practically copied the USSR-France one.
As it was already said, the relations USSR-USA were not stable as well. The USA remained the only Great Power, which didn't recognise the USSR. Americans demanded, as a preliminary step, repayment of all the debts as well as compensation for the damage American businessmen had suffered as a result of the post-revolution expropriation. Nevertheless in the late 20-s the Soviet-American trade developed successfully. In 1930 the Soviet Union took the second place in import of American machines and equipment, and in 1931 - the first place. In summer of 1930 Washington used discrimination measures against Soviet export. That led to the situation, that the USSR had to decrease import from the USA - it went down more than 8 times as lesser. Anyway on 16 November, 1933 a considerable progress was achieved in Soviet-American relationship: diplomatic relations were set up.
The USSR-Germany relationship in the 20-s were rather successful. Mutual trade developed favourably enough. In Autumn of 1934 USSR-Germany talks began about a many-sided agreement on mutual aid (the so-called Western Pact), in which the USSR participated. Germany's refusal from participating, as well as Poland's, non-constructive policy of Great Britain led the negotiations to a deadlock.
In 1935 the USSR disapproved introducing in Germany (in defiance of Versal Peace Treaty) total compulsory military service and Italy's intervention into Ethyopia. The USSR rendered a considerable aid to Spain republican government, sending regular troops to the country under the pretence of volunteers.
Real contacts between England, France and the USSR apropos of German threat began in March, 1939. In April of 1939 experts of the three countries began to consider draft agreements on mutual aid in connection with the would-be German aggression. The negotiations advanced with much difficulty. No side wanted to accept unambiguous obligations. The talks came to a full stop.
Practically simultaneously with the beginning of the talks between England and France since spring of 1939 the USSR started to reconnaissance German positions relatively a possible rapprochement. In his turn Hitler was exceedingly interested in a sooner learning about Soviet positions , since he used all the possibilities of assignments from the West and decided to try to unfix the international system with the help of the East.
Having come to a deadlock on the negotiations, Soviet administration went into rapprochement with Germany. In August of 1939 German minister for foreign affairs Ribbentrop and V. Molotov as the USSR Minister for foreign affairs, signed Pact of mutual non-offence. In a additional secret protocol "spheres of influence" of Germany and the USSR in Eastern Europe were divided: Almost the whole of Poland was to be German sphere of interest, and a small portion of Eastern Poland, Lithuania, Latvia, Estonia, Finland, some other regions became sphere of USSR influence.
Thus the USSR returned the regions of the former Russian empire. Signing the Pact led to cut-off in the relations between the USSR from one side and England and France from the other. English and French delegations were recalled from Moscow.