As this is a high-risk-low-return strategy for the winning side, already defeated side, or ill-matched opponent (difference of personal standing or martial reputation) it was acceptable to decline or elude the single combat. An example of single-combat with the tragic result for the victor is told in Heike Monogatari as Kumagai Naozane defeated Taira no Atsumori at the Battle of Ichi-no-Tani. It could be banned by the overall commander as needed and notably during Mongol invasions of Japan, particularly during the second invasion in 1281, samurai fought as massed mounted archer/warrior with the annihilation of enemy as the goal. This tradition declines and disappears during the Sengoku period as each side prepared trained armies in thousands or even tens of thousands making the single combat have a limited, if any, effect on the outcome of the battle. In Russia, single combat is known as "bash na bash" (an old Russian expression meaning "one-on-one"), substituting a fight between champions for a full-scale battle was a traditional way to avoid the bloodshed of an internecine war. The leaders of the opposing "druzhinas" or other armed groups either rode towards the centre of the battlefield or sent messengers to negotiate whether the two most skilled fighters or the leaders themselves would engage in single combat, usually to the death. The outcome of the champions' fight would then be taken as a sign of which side the higher powers favoured, and could have political consequences similar to the result of a full battle. The oldest written account of such a fight is found in Nestor's' "Primary Chronicle"; it describes a duel between a Kievan champion and the Pechenegs' best fighter. The most well-known fight, however, was that between Prince Mstislav the Brave of Tmutarakan and the Kasog Prince Rededia in 1022, in which Mstislav defeated Rededia and killed him with a dagger. According to the "Primary Chronicle", Mstislav's victory allowed him to take tribute from the Kasogs and to have a church built; he also took Rededia's wife and two sons and had them baptised into Christianity, upon which he had his daughter married to Rededia's son according to the tradition of the times. Although Rededia had been killed, he was honoured by Mstislav, and his family joined the ranks of the Russian nobility.