The official border between Novgorod and Sweden was established in 1323. When Novgorod became part of the Moscow Kingdom, an agreement was signed to preserve the border. But boundary Commission met only in 1518.
Most of the border on the Karelian isthmus passed along the rivers. There were almost no alternatives on their navigable sections. But a lot of them were in the upper reaches of the small rivers: as with the selection of the main channel of the top sleeve, and with the determination of land plot boundaries between the sources. The dispute gave rise to the toponym Riitamaa.
On the eve of 1595, both sides wanted to keep the border 1323. But first had to find it on the ground. The main difficulty of the negotiations was that both sides tried to deceive their partners.
Summer 2018 the author examined the place in search of Ristikivi mentioned in various documents. Suddenly there were three such stones at once. They correspond to three variants of the boundary line:
1) Novgorod-Swedish border 1323;
2) Moscow-Swedish border 1518;
3) Moscow-Swedish border 1595.
Russian twice moved the border to the West for about a kilometer. Moreover, the Prince Zvenigorodsky was trying to move the border up to 20km. The incentive to cheat was the fortress of Ruuneta trapped under the agreement 1323г. on the Swedish side. It was in the common source of the four largest (after the Neva and Vuoksa) rivers of the isthmus and protected the draughts between their sources.