Nikifor Romanovich Chernigovsky (died in 1675; Polish: Nicefor Czernichowski, also known as Jaxa-Czernichowski and Czernihowski, Russian: Никифор Романович Черниговский) was a Polish noble who is notable for establishing the micro-nation of Jaxa. He fought in the Russo-Polish War of 1654-1667, where he was captured by the Russians and was exiled to Siberia.^[1]

Nikifor Chernigovsky was imprisoned by Russians in 1633 during the battle near Novhorod-Siverskyi. He was exiled to Vologda. When the Russo-Polish war ended, he was given freedom. Chernigovsky had married a woman from Moscow during his exile, and so intended to stay in Russia (specifically, the state of Muscovy.) He swore loyalty to the Tsar and converted to Orthodoxy in 1635.

Despite all this, in 1636 he changed his mind and decided to try and go back to Poland. Since this was a betrayal of his loyalty to the Tsar, he was captured and sent back into exile in Yeniseysk. He arrived with his wife in 1637. In 1649, he was sent further east, to the settlements of Ilimsk, Ust-Kut and Kirensk. During this time, he had three sons and two daughters. In 1656 he became a notable leader of Cossacks. In 1657, he attempted to have his nobility officially acknowledged by the Tsar of Russia, but he was left unanswered.

In 1664, the Voivode (military leader) of Ilimsk Lawrentij Obuhov raped Chernigovsky's daughter Pelagia. Nikifor murdered Obuhov in an act of revenge in 1665. For this, Nikifor became an outlaw. Fleeing Russian law, he organized a group of about 80 Cossacks and traveled to the Russian-Chinese border, specifically the Amur river. They settled in the abandoned settlement of Albazin.

Nikifor founded a small kingdom with the local Siberian Duar people, naming it Jaxa after his coat of arms. His state was not officially acknowledged by either Russia or China. The state only had about 500 people.

From the beginning, Nikifor's international position was very strange. After some struggles with Russia, Nikifor declared in 1669 that Russia was their overlord, but Jaxa was still an independent state. In 1670, Jaxa successfully defended itself from a minor Chinese attempt at conquering it. In 1672, the Tsar of Russia issued a death sentence against Nikifor, but two days later the Tsar decided to show mercy and not enforce it.

Some Duar people had been forcibly moved from regions near Jaxa and into Manchuria. In 1675, he was called by these Duar people to free them so that they could join the state of Jaxa. Nikifor decided to lead a small military expedition into Manchuria. He most likley died during his expedition.

Jaxa was annexed by China in 1685.

• Knowledge and Life – A Different Side of History at the Wayback Machine (archived 20 October 2011) (in Polish)