Osaka-born Mayo Shouno's（庄野真代）5th single, "Tonde Istanbul"(Fly Istanbul), was another example of kayo kyoku's seeming interest in Central Asia and Europe during the late 70s. The exotic sound here, though, was a bit more subdued when compared to Saki Kubota's "Ihojin" and Judy Ongg's "Miserarete". I'd say that there was more of an even mix between the usual kayo kyoku and the exotic sound so that it may have been one of the first examples of what has been called European enka.
Released in April 1978, "Tonde Istanbul"was created by lyricist Tetsuya Chiaki（ちあき哲也） and composer Kyohei Tsutsumi（筒美京平）. It went as high as No. 3 on the Oricon charts, and sold more than 600,000 records. In addition, it and the following single, "Monte Carlo de Kanpai"（モンテカルロで乾杯....Here's to Monte Carlo) earned Shouno an invitation to that year's Kohaku Utagassen. The song is also available on her 4th album, "Refrain"(1978). Overall, the song was the 19th-ranked song of the year.
According to J-Wiki, Shouno made her first visit to Turkey a couple of years after releasing the biggest hit of her career, and was rather shocked initially:
"I arrived in Istanbul after a long-distance bus ride from Greece, and it was snowing there! The humidity was high, though. We didn't have the Internet to collect any information, so I was surprised to see this weather since 'snow' and 'exotic' don't match at all."
My advice: July is better.