Turkey's President Recep Tayyip Erdogan visited China and negotiated over a controversial deal with Beijing to buy sophisticated air defense systems.

The visit is yet another twist in the long-running drama of Turkey's multi billion-dollar air defense deal, which has become a litmus test of sorts for its geopolitical leanings. The controversy kicked off in 2013, when Turkey announced it would opt for a Chinese system over American and European bidders. That, in turn, sparked harsh reactions from NATO allies and it had increasingly seemed that Ankara was getting ready to change its mind and opt for the European system after all.

But ahead of his July 28-29 visit to Beijing Erdogan suggested that air defense was part of the agenda. "The most suitable bid came from China but certain developments led to delays. We will revisit these matters during this trip. If we receive a proposal that enriches the bid, we will view this positively," Erdoğan told a news conference in Ankara before departing for China. 

"The visit's most important topic will be the negotiations between China and Turkey on defense systems," an unnamed Turkish official told Turkish newspaper Today's Zaman. 

NATO's primary objection to Turkey buying the Chinese system was that it would not be able to be securely integrated into NATO's own air defense system, of which Turkey already plays a large part. Turkey, meanwhile, has argued that its highest priority is getting access to the technology used to built the system so that it can eventually build them (or something similar) itself; China was willing to that (in addition to being a cheaper offer) while the European bidder weren't. 

So this passage, from a different Today's Zaman story, is curious:

An official from Turkey's Defense Industry Undersecretariat, which has run the technical negotiations with China, said a major stumbling block has been China's reluctance to make a technology transfer which could give Turkey the knowledge to operate the system and eventually replicate it. "If this issue is solved, the project will be approved," the official said on condition of anonymity. But Erdoğan may also field complaints about recent protests, some violent, against China's embassy and citizens in Turkey by nationalist Turks angered by China's treatment of Uighurs.

So has something changed in China's offer of technology transfer? 

Anyway, nothing was announced on missile defense as a result of the visit. Chinese Deputy Foreign Minister Zhang Ming told reporters after Erdogan's meeting with Chinese President Xi Jinping only that both sides have "strong interests in defense cooperation and will strengthen cooperation in this area." (Today's Zaman anonymous source, for what it's worth, said ahead of the visit that no announcement was expected.) Anyway, does all this mean that  China back in the game again?