Complex sentence: A telegraph line from Vladivostok to Shanghai and Nagasaki was opened in 1871, the year when a commercial port was relocated here from Nikolayevsk-on-Amur.
Split into simpler sentences: A telegraph line from Vladivostok to Shanghai and Nagasaki was opened in 1871. That same year a commercial port was relocated to Vladivostok from Nikolayevsk-on-Amur.