Mr Xi held talks with South African President Cyril Ramaphosa on the eve of the gathering, saying that "the Johannesburg summit has special significance for Brics cooperation in the new circumstances". "Access to the global economy through trade has underpinned China's economic success over the past two and a half decades".
US President Donald Trump has imposed billions of dollars of tariffs on Chinese goods to retaliate for what he says are unfair practices that have resulted in a huge trade imbalance.
Chinese President Xi Jinping said there would be no victor in a global trade war, urging fellow developing powers on Wednesday to reject unilateralism in the wake of tariff threats by US President Donald Trump.
Trump has said he is ready to impose tariffs on all US$500 billion of Chinese imports, complaining that China's trade surplus with the U.S. is due to unfair currency manipulation.
Modi will attend the 10th edition of the BRICS Summit in Johannesburg, during which the grouping's leaders are expected to deliberate on global hot-spot issues, worldwide peace and security, global governance and trade issues among others.
"The concern that South Africa has with the protectionist policies by President Trump at this stage, is that it is playing havoc with the local market".
China to invest $14b in South Africa
"They come with the national interests of their countries".
Sreeram Chaulia, of the Jindal School of International Affairs outside Delhi, told AFP that BRICS leaders "concur that the United States has unleashed punitive trade wars that are hurting all the BRICS members".
Ramaphosa, who has promised to revive the economy since becoming president in February and after winning the leadership of the ruling African National Congress past year, said "Xi has indicated that China is ready to invest and work with South Africa in various sectors".
Earlier, Modi had visited Rwanda for two days on the first leg of his visit. "He has just secured another big investment, this time from China".
Xi's counterparts from Russia, Brazil and India will join him at the summit, as will Turkish President Recep Tayyip Erdogan and African leaders such as Angola's João Lourenço and Zambia's Edgar Lungu.
Microsoft's annual revenue crosses $100 billion for first time
Microsoft's Surface business also saw significant growth for the quarter, posting a 25 percent gain over the same time past year . For fiscal 2018, Microsoft reported net income of $16.6 billion, or $2.13 a share, on revenue of $110.4 billion, up 14 percent.