Kasar Sin wadda a yanzu karkashin Deng Xiaoping ta fara yin gyare-gyare a fannin tattalin arzikin kasar Sin, da bude kofa ga kasashen yammacin duniya, kuma tana kara nuna adawa da Tarayyar Soviet .Kasar Sin ta damu matuka game da tasirin Soviet mai karfi a Vietnam, tana tsoron cewa Vietnam za ta iya zama mai kare Tarayyar Soviet.Ikirarin da Vietnam ta yi na zama kasa ta uku a duniya a karfin soja bayan nasarar da ta samu a yakin Vietnam ya kuma kara fargabar kasar Sin.A ra'ayin kasar Sin, Vietnam na bin manufofin hegemonic na yanki a yunƙurin sarrafa Indochina.A cikin watan Yuli na shekarar 1978, ofishin siyasa na kasar Sin ya tattauna yiwuwar daukar matakin soja a kan Vietnam don kawo cikas ga sojojin Soviet, kuma, bayan watanni biyu, Babban Jami'in PLA ya ba da shawarar daukar matakan hukunta Vietnam.^[222]Babban rugujewar ra'ayin Sinawa game da Vietnam ya faru ne a cikin Nuwamba 1978. ^[222] Vietnam ta shiga CMEA kuma, a ranar 3 ga Nuwamba, Tarayyar Soviet da Vietnam sun rattaba hannu kan yarjejeniyar tsaro na shekaru 25, wanda ya sanya Vietnam ta zama "linchpin" a cikin shekaru 25. Yunkurin da Tarayyar Soviet ta yi don ɗaukar kasar Sin” ^[223] (duk da haka, Tarayyar Soviet ta kau da kai daga ƙiyayyar ƙiyayya ga dangantakar da ke tsakaninta da Sin ba da daɗewa ba).^[224] Vietnam ta yi kira ga dangantaka ta musamman tsakanin ƙasashen Indochine uku, amma mulkin Khmer Rouge na Democratic Kampuchea ya ƙi ra'ayin.^[222] A ranar 25 ga Disamba 1978, Vietnam ta mamaye Democratic Kampuchea, ta mamaye yawancin ƙasar, ta kori Khmer Rouge, kuma ta sanya Heng Samrin a matsayin shugaban sabuwar gwamnatin Cambodia.^{[225 <]} > Matakin ya ɓata China, wanda a yanzu ke kallon Tarayyar Soviet a matsayin mai iya kewaye iyakar kudancinta.^[226]Dalilin da ya sa aka kai harin shi ne don tallafa wa kawancen kasar Sin Khmer Rouge na Cambodia, baya ga musgunawa 'yan kabilar Vietnam 'yan tsiraru da kuma mamayar da 'yan Vietnam suka yi a tsibirin Spratly da kasar Sin ta yi ikirarin cewa.Don hana tsoma bakin Soviet a madadin Vietnam, Deng ya gargadi Moscow a washegari cewa, Sin ta shirya tsaf don yaki da Tarayyar Soviet;A shirye-shiryen wannan rikici, kasar Sin ta sanya dukkan sojojinta da ke kan iyakar kasar Sin da Soviet cikin shirin ko-ta-kwana, ta kafa wani sabon kwamandan soja a jihar Xinjiang, har ma ta kwashe fararen hula kimanin 300,000 daga kan iyakar Sin da Tarayyar Soviet.^{[227 <]} > Bugu da ƙari, yawancin sojojin Sin (dakaru miliyan ɗaya da rabi) sun kasance a kan iyakar China da Tarayyar Soviet.^[228]A watan Fabrairun shekarar 1979, sojojin kasar Sin sun kaddamar da wani farmaki na ba-zata a arewacin Vietnam, inda suka yi gaggawar kwace garuruwa da dama da ke kusa da kan iyaka.A ranar 6 ga Maris na wannan shekarar, kasar Sin ta ba da sanarwar cewa, an bude "kofar zuwa Hanoi" kuma an cika aikinta na hukunta masu laifi.Daga nan ne sojojin China suka janye daga Vietnam.Duk da haka, Vietnam ta ci gaba da mamaye Cambodia har zuwa 1989, wanda ke nufin cewa Sin ba ta cimma burinta na kawar da Vietnam daga shiga Cambodia ba.Amma, aikin da kasar Sin ta yi a kalla ya yi nasarar tilastawa Vietnam janye wasu runduna, wato rundunar soja ta 2, daga mamayar Cambodia don karfafa tsaron Hanoi.^{[229 <>]} Rikicin ya yi tasiri mai ɗorewa a dangantakar dake tsakanin Sin da Vietnam, kuma dangantakar diflomasiyya a tsakanin ƙasashen biyu ba ta cika ba sai a shekara ta 1991. Bayan wargajewar Tarayyar Soviet a shekara ta 1991, an kammala iyakar Sin da Biyetnam.Ko da yake ba za ta iya hana Vietnam daga korar Pol Pot daga Cambodia ba, Sin ta nuna cewa Tarayyar Soviet, abokiyar kwaminisanci ta Cold War, ba ta iya kare kawayenta na Vietnam.^[230]