Firepower has been crucial in Russia’s gains in the war, but Ukrainian fighters and analysts say that Moscow has relied increasingly on a more crude tactic as its forces try to take the eastern city of Bakhmut: the sheer weight of troop numbers. Russian casualties in recent fighting in Bakhmut have been higher than in previous months as commanders have poured soldiers into the battle, the Ukrainians said. The Kremlin is aiming for a significant victory after suffering battlefield setbacks in the south and northeast last fall and as both sides prepare for offensives in the coming weeks or months....