North Korean state television showed Kim Jong-un waving to top government and military officials as he left Pyongyang on his bulletproof train for Russia.
Vladimir Putin, attending an economic forum in the eastern city of Vladivostok, is expected to greet Kim with the full honors of a state visit.
"A new model of mutual relations and integration is being born, but not on a basis of Western standards", Putin said.
There's a more practical reason for the rare summit, too.
North Korea produces artillery and missiles, which it aims at South Korea.
But since the two Koreas haven't fought a war in decades, the North has vast stockpiles of the weapons,
which Putin needs now to fend off Ukraine's American-backed counter-offensive.
Putin's Defense Minister was in Pyongyang in July to discuss an arms trade.
It's unclear what Putin would give Kim in return, but it's expected to include food and support for North Korea's advanced weapon systems.
Kim just oversaw the launch of what North Korea called its first tactical nuclear attack submarine.