Introduction:

The interactions of economies have caused the sensitivity to choose import sources, target markets and trade partners in general. Each country chooses its own trade partners based on its coordinates in order to minimize its import costs and generate maximum export income while avoiding the negative effects of international economic fluctuations. Diversification of trade partners is one of the ways to strengthen of an economy and reduce the vulnerability against international economic fluctuations and shocks. Diversification of import sources and export destinations of each country can lead to the stability of foreign trade and increase the stability of domestic production. In Iran's economy, due to the special conditions, such as economic sanctions, this issue is of double importance. In the previous periods of sanctions (before 2017), one of the weak points of Iran's economy has been the decrease in diversity in the mix of foreign trading partners, which includes the decrease in the number of buyers of oil (as Iran's main export product), the decrease in the arrival of foreign tourists, and the reduction of countries exporting goods to Iran. In this situation, two countries, China and Russia, became Iran's main trade partners, and to some extent, it reduced the impact of Western economic sanctions against Iran's economy. Meanwhile, in the last two decades, China has practically become the main competitor and substitute for the economic powers of the world, known as the OECD member countries, and has acquired large markets in South and East Asia, the Middle East and Africa. Therefore, it can be said that diversification of trade partners for all countries of the world practically means creating opportunities and for Iran, it means a way to survive.



Methodology:

The present research is based on the "Locomotive theory", which expresses the influence and effectiveness of the economic fluctuations of countries on each other through foreign trade. For this purpose, two models with the same structure were designed for two periods during 1970- 2018 to investigate the role of China's presence or absence among Iran's trading partners using the structural vector auto-regression (SVAR) model. According to the "Locomotive theory", international economic fluctuations affect countries through foreign trade, and only a few countries have the potential to bring countries out of the crisis. This theory states that during 1975-77, the United States was the main "locomotive" to pull out the world economy (more precisely, the industrialized countries) from the previous recession (the first oil shock), and paid a very high price for it, and it was necessary for America's major partners in that period, especially Japan and Germany, to accept their role as the locomotive of the world economy and in this way help both the American economy and the world economy. This theory specifically states that industrialized countries are the sources of international economic fluctuations and their prosperity or recession first spreads to major partners and with a delay to other countries.

The monetary and financial policies of the United States have played a decisive role in the development of global economic cycles through trade and financial links with smaller countries. In recent decades, although the importance and role of the United States has remained, but the US economy is not growing fast enough to act as the sole locomotive of the world economy train, especially in the last decade. China alone, and other major emerging markets as a whole, have become important drivers of the global economy. China and other major emerging markets are increasingly interdependent. Because on the one hand, China is the main importer of raw materials, and on the other hand, it is a supplier of manufactured products and foreign investment. The occurrence of such a phenomenon in the field of international economy has attracted the attention of many researchers to discuss the role of business partners and examine the unilateral and mutual effects of such decisions.

According to a study conducted in 2015 by Assoumou Ella for Kenya, the trade relationship between a third world country and industrialized countries is drawn in the presence of an emerging economy. In this research, the same model is used for Iran's economy. For this purpose, in the present study, based on the theoretical and experimental literature of this field a structural vector auto-regression (SVAR) model has been designed and specified. The first reason for using this model is its design based on the theoretical structure, and second reason is to provide a framework in which a variable, while being endogenous, is affected by other endogenous variables; but it should not affect them. The second case is very important regarding Iran's economy; because the macroeconomic variables of Iran's economy for several reasons (weak structure of Iran's economy, the issue of sanctions, customs tariffs) have no significant effects on the macroeconomic variables of trading partners included in the model.

Results and Discussion:

The results of the analysis of the reaction functions show that in most cases, the fluctuations of the macroeconomic variables of Iran (including GDP, inflation, FDI, export and import) have decreased in response to the fluctuations of GDP and inflation of OECD countries after the inclusion of China in the model. So that the intensity of the impact of the shocks entered into the model has become milder and the time for disappearing of the shocks has also been shortened.

Conclusion:

The results show that the diversification of Iran's Trade partners during the mentioned period has reduced the effect of the economic fluctuations of OECD countries on the macroeconomic variables of Iran. This means more stability of Iran's economy, so diversification of trade partners leads to resiliency against international crises, especially in the context of sanctions.