Ian Heath, "Armies of the Dark Ages", caption to fig.74 "Rus Warrior": "Leo the Deacon records that a great many [Rus] wore mail corselets; he also says that they fought with swords, bows, spears and javelins and carried long shields "the height of a man"; clearly the tall rectangular shields of Slav origin described under 103 in "Armies of Feudal Europe".".
"Armies of Feudal Europe", under figure 119 (second edition; it's certainly not "103" in that edition), has a Polish heavy infantryman carrying the same rectangular shield: "The rectangular wooden shield is a typical Slav design and was used in Russia, and possibly Serbia and Bulgaria too, at this date. It was flat, often painted, and had an iron rim, boss and ornament. From the rims and other remains of such shields that have been found, Polish archaeologists estimate that they were about 120 cm (nearly 4 feet) tall…"
Under 134-5, Russian militiamen 11th-13th centuries, Heath says "The painted circular shield carried by 134 … was used by most infantry, particularly in central and northern Russia. However, in the east and south the rectangular Slav shield described under 119 prevailed."
That's all I know, I think.
