Article 31. In the Democratic People's Republic of Korea the minimum working age is 16 years. The State shall prohibit the employment of those under the minimum working age. Article 32. The State shall firmly adhere to the principle of properly combining political guidance with economic and technical guidance, the unified guidance of the State with the creativeness of each unit, unitary direction with democracy, and political and moral incentive with material incentive and assuring benefit in the guidance and management of the socialist economy. Article 33. The State shall operate and manage the economy scientifically and rationally on the basis of the collective wisdom and efforts of the producer masses, and will decisively increase the role of the Cabinet. The State shall enforce the socialist enterprise self-accounting system in economic management, and shall make proper use of such economic levers as cost, price, and profit. Article 34. The national economy of the Democratic People's Republic of Korea is a planned economy. The State shall draw up and implement the plans for the development of the national economy in accordance with the laws of socialist economic development so that the balance between accumulation and consumption can be maintained correctly, economic construction accelerated, the people's standard of living steadily raised and the nation's defence capabilities strengthened. The State shall ensure a high rate of growth in production and a balanced development of the national economy by implementing unified and detailed planning. Article 35. The Democratic People's Republic of Korea shall compile and implement the State budget according to the national economic development plan. The State shall systematically increase its material accumulation and expand and develop socialist property by intensifying the campaign for increased production and greater economy and by exercising strict financial control in all spheres. Article 36. In the Democratic People's Republic of Korea foreign trade is conducted by the State organs and enterprises, and social, cooperative organizations. The State shall maintain credibility, improve trade patterns, and grow and develop foreign trade relationships on the principles of complete equality and mutual benefit. Article 37. The State shall encourage institutions, enterprises and organizations in the country to conduct equity or contractual joint ventures with foreign corporations and individuals, and to establish and operate enterprises of various kinds in special economic zones. Article 38. The State shall pursue a tariff policy to protect the independent national economy.