Monday will mark the official start of spring in the Slavic world. In Ukraine, it will mark the failure of two winter offensives by Russia.

In the first, Russia dispatched 15 successive air waves of missiles and drones at Ukraine’s electricity and heating plants. The six-month air blitz was designed to break Ukrainian morale by making 35 million people freeze in the dark. The 1,000 missiles and 1,000 drones caused $7 billion worth of damage and enormous hardship.

American Patriot air defense systems have yet to be installed in Ukraine. Ukrainian gunners, though, learned to shoot down 80 percent of incoming missiles and drones. Ukrainian electricity workers learned to repair transformers faster than they could be blown up. Just as Hitler’s Blitz failed to break the British fighting spirit, President Putin’s winter blitz caused Ukrainians to dig in their heels. On Monday, temperatures in Kyiv are to hit 56 degrees Fahrenheit.

The enormity of Russia’s second, less visible, offensive now is coming into focus. In the first ten weeks of this year, an estimated 50,000 Russian soldiers were killed in southeastern Ukraine. This is more than three times the 14,553 Soviet soldiers killed during the whole decade of the Soviet Union’s occupation of Afghanistan.

In the 1980s, the Soviet Union had a population of 288 million — twice as large as modern Russia’s population of 144 million. In the Vietnam War, 58,220 American soldiers died between 1955 and 1975. In 1970, the American population was 203 million.

Drawing on field reports and drone footage of battlefields littered with abandoned corpses, Ukraine’s Defense Ministry calculates that 53,080 Russian soldiers have been killed in Ukraine since Jan. 1. (Please see marker 4:15 on Denys Davydov’s drone video of a battlefield near Bakhmut.) 

Two weeks ago, the Supreme Allied Commander in Europe, General Christopher G. Cavoli of the U.S. Army, said that more than 200,000 Russian soldiers have been killed or wounded since Russia launched its invasion of Ukraine one year earlier. Speaking in Germany, he said that over 1,800 Russian officers were killed or wounded. A Russia expert, General Cavoli described Russia’s losses as “unbelievable.”

Ukraine has lost thousands of soldiers this winter in its defense of the provincial city they call “Fortress Bakhmut.” Traditionally, a defending force has a three to one advantage over an attacker. In Bakhmut, NATO analysts say the ratio is five to one, favoring Ukraine. On Friday, the Ukrainian national security chief, Oleksiy Danilov, estimated the ratio at seven to one.

These are the kind of casualties suffered by Japanese soldiers in the human wave attacks on American troops in World War II. This high kill rate explains why Ukrainian commanders decided today to hold Bakhmut. They aim to weaken Russia’s military as much as possible before an expected May-June counter-offensive.

“The real heroes now are the defenders who are holding the eastern front on their shoulders, and inflicting the heaviest possible losses, sparing neither themselves nor the enemy,” the Ukrainian ground forces commander, Oleksandr Syrskiy, said Saturday. “It is necessary to buy time to build reserves and launch a counteroffensive, which is not far off.”

As many as half of the Russian soldiers killed this winter are convicts recruited from prisons and sent almost directly to the front with minimal training. Captured soldiers told Ukrainian interrogators of being forced forward at gunpoint, and threatened with execution if they retreated. This use of prisoners is part of a deliberate strategy to recruit from segments of society that pose the lowest threats to the Kremlin.

In “Russia’s Last Peasant War,” London-based analyst Vladimir Pastukhov argues that this recruitment strategy represents “a war between ‘small Russia’ and ‘big Russia.’” By drafting men from villages and from ethnic republics far from Moscow, Mr. Putin can keep political pressure low in Russia’s influential ‘millioniki’ — the 14 cities with populations of one million or more.

In “Ideological Fighters are Dangerous,” a follow-up essay on Ekho Moskvy’s news site, Mr. Pastukhov writes that Mr. Putin avoids a mass draft because it would arm nationalists. These fighters might question why Mr. Putin is bleeding Russia dry with a war against a brother Slavic nation.

To replenish ranks, Russian mercenary chief Yevgeny Prigozhin said Friday that his Wagner private army has opened recruitment centers in 42 cities across Russia. But Russians note that Wagner and Russian Army soldiers have been trying to take Bakhmut since August. They grumble that Soviet Army soldiers took Berlin in 16 days in 1945, while Russian soldiers have besieged Bakhmut for almost eight months.

“In general, Russia’s winter offensive has been rather lackluster,” Russian military expert Michael Kofman told a Carnegie Endowment for International Peace forum Monday. Fresh from a tour of Ukraine’s front lines, including Bakhmut, he predicted: “We will see a major offensive by the Ukrainian military in coming months.”

Without a battlefield victory since last summer, Russia’s manpower shortage comes as the country runs short of arms and ammunition. The latest air attack on Kyiv, last Thursday, featured Kinzhal (dagger) missiles. These air-launched, hypersonic missiles are difficult to shoot down, but there are believed to only be 15 in existence. Instead, Russia increasingly fields antique, Soviet-era equipment. The T-62 tank entered service in 1961. The BTR-50 tracked infantry transporter entered service in 1954. And the AK-47 automatic rifle entered service in 1949.

By contrast, in the first four months of this year, America and NATO allies are sending more military equipment to Ukraine than was sent during all of last year. Hundreds of Bradley Fighting Vehicles and dozens of German Leopard tanks are to be in Ukraine by May 1. At the same time, an estimated 10,000 Ukrainian soldiers and officers are training in NATO nations.

With a major Ukrainian counter-offensive expected for May-June, China’s leader, Xi Jinping, is to visit Moscow next week, his first visit in four years. After meeting with Mr. Putin, Mr. Xi is expected to call President Zelensky, reports the Wall Street Journal. Mr. Xi has met Mr. Putin in person 39 times. He has never talked with Mr. Zelensky.

Despite a proclaimed partnership “without limits,” China has held off sending military aid to Russia during the year-long war. Today, it seems unlikely that China could rush large amounts of  Soviet-standard ammunition and equipment to Russia before Ukraine’s counter-offensive starts. Presumably, Mr. Xi will use the threat of military aid to push Ukraine to settle for a ceasefire, perhaps an armistice similar to the one that has kept the peace on the Korean peninsula since 1953.

With Russia’s military outlook dire, Beijing prefers a weak Mr. Putin over regime change. A new Russian leader could take a pro-Western stance in order to get Russia out of economic sanctions. A weak Mr. Putin would keep the peace on the 2,615-mile Sino-Russian border and would give China preferential access to Russia’s raw materials. In Moscow, people already joke: “The next Iron Curtain will be made in China.”