On the import side, Bruening’s government had successfully lowered purchases at the cost of mass unemployment and Hitler did not repeat his mistakes. One legacy the Weimar period did leave was the system of foreign exchange rationing: exporters handed the foreign currency they gained to the Reichsbank, which repaid them in Reichsmarks and distributed it to importers. Germany thus had a mechanism to reduce imports by handing out less currency, which it extensively did. And in 1934 the RWM (Business Ministry) set up surveillance agencies (Ueberwachungsstellen) to organize the rationing of commodity imports in some sectors, such as wool, cotton and nonferrous metals.

Those were still ad hoc measures and importers found loopholes around them, so a bureaucracy had to be set up to institutionalize the system. From August 1934 the Reichsbank would allocate foreign currency based on export returns, keep some to pay debt and hand over the rest to 25 supervisory agencies, one for each kind of commodity. Prospective importers would file applications to their agency, which then doled out its limited funds to imports deemed of higher priority. Successful applications resulted in Exchange Certificates (Devisenbescheinigungen), without which imports were banned.
Besides lowering imports, this structure was used to direct resources to key industries at the expense of those of lesser importance to the state’s goals. Hence, through the 30s the textile industry stagnated while the military-industrial complex boomed. It also magnified the dominance of raw materials within the composition of German imports. As a side effect, industrialists no longer had to worry about competition with foreign manufactured goods within the internal market.

Germany’s commercial relations were revised to improve the balance of trade. What resulted was not “autarky” in the full sense of the word: mercantile disengagement happened just with France, Britain, and, primarily, America. A trade deficit with the USA existed and remained, but the total volume of trade shrank from a few billions to just hundreds of millions of Reichsmarks. Transatlantic diplomatic relations deteriorated at the same rate.
With other trading partners, Germany rejected multilateralism and sought bilateral deals with each. In Western Europe, threats of moratorium broke European-American coordination and allowed agreements with the Netherlands, Switzerland, and even Britain; a trade war with the latter would have been damaging for both parties.
To replace raw materials no longer provided by America and Britain, German trade made inroads in Latin America and Southeast Europe. Copper and saltpetre came from Chile, wheat and maize from Romania, Hungary and Yugoslavia, oil from Romania, cotton from Brazil and Peru and coffee from Brazil. This had geopolitical consequences: Southeast Europe was drawn into a German sphere of influence and Brazil found itself in a better position to handle its American debt.

Another aspect of import reduction was investment in technologies such as synthetic fuel and rubber.

Imports were thus squeezed as much as possible. Nonetheless, some (not all) industries were still expanding through the 30s and demanding more and more imported raw materials. With supply restricted and booming demand, there was a tendency towards inflation. To prevent this, rationing was implemented for commodities themselves and not just the foreign currency to buy them. Most importantly, steel was rationed from 23 January 1937. Initially rationing was balanced and rearmament didn’t receive as much steel as one would expect, but later on this, too, became a mechanism for focusing resources on the military-industrial complex.