In the article, the author addresses to the problem of determining the starting point of hybrid aggression against the Ukraine. Hybrid aggression quite often stands outside the legal field and it makes it difficult to determine the exact date of the start of the aggressive action. Several options were singled out for Ukraine – the beginning of the 1990’s, 2006, the election of Viktor Yanukovych, summer 2013, Euromaidan and February 2014. The author concludes that irreversible consequences for Ukraine had events (...) on February 20, 2014. It is also shown the periodization of Ukrainian-Russian relations from the point of view of falling into hybrid confrontation. Russia launched unfriendly actions against Ukraine not immediately. There are reasons to believe that the «cassette scandal», which in 2000 led to the political isolation of Leonid Kuchma in the West, was initiated by Moscow. After the Orange Revolution Russian elites where frightened seriously and the Kremlin began to prepare to neutralize the possible increase of Ukrainian influence in the post-Soviet space. The 2001 to 2014 period can be attributed as the time of search for forms and methods of realization of new geopolitical intentions. Volodymyr Horbulin suggests that approximately in the mid-2000’s such a solution was found – «asymmetric responses» within a larger «hybrid war». Finally, author notes that chronology is an instrument for deeper understanding of phenomena and processes. Expansion or conversely narrowing the chronological boundaries allows you to choose a different angle of view of the events, sometimes even look deeper and differently to set accents, better understand the essence of the events. Neither the confrontation on the island of Kosa Tusla nor gas and trade wars or murders on the Maidan, did not cause irreversible consequences. Those who violated Ukrainian sovereignty and territorial integrity were endangered by the very existence of the Ukrainian state. Such effects appeared on February 20, 2014 and the subsequent actions of «green men» in the Crimea. (shrink)