China and Russia each share a common border with 14 other countries. According to the CIA, the countries and length of their borders are:
China: Afghanistan 76 km; Bhutan 470 km; India 3,380 km; Kazakhstan 1,533 km; North Korea 1,416 km; Kyrgyzstan 858 km; Laos 423 km; Mongolia 4,673 km; Myanmar (Burma) 2,185 km; Nepal 1,236 km; Pakistan 523 km; Russia 3,645 km; Tajikistan 414 km; and Vietnam 1,281 km.
Russia: Azerbaijan 284 km; Belarus 959 km; China 3,645 km; Estonia 294 km; Finland 1,313 km; Georgia 723 km; Kazakhstan 6,846 km; North Korea 19 km; Latvia 217 km; Lithuania 227 km; Mongolia 3,441 km; Norway 167 km; Poland 206 km; and Ukraine 1,576 km. (Note: Lithuania and Poland only border Kaliningrad, a Russian section separated from the rest of the country.)