US Secretary of State Rex Tillerson begins a series of meetings in Asia this week with the region in a military turmoil.
North Korean missiles streaking toward Japan.
US anti-missile batteries arriving in South Korea.
China's foreign minister fearing a massive military confrontation is about to happen.
China's state news agency openly speculating Asia is on the verge of a nuclear arms race, the likes of which has not been seen since the Cold War.
Each one of these things alone would be enough to destabilize the status quo.
Taken together, they have placed tensions in North Asia on a knife's edge.
Should they tip over, who would come out on top? What are the strengths and weakness of the forces that would fight a North Asian war.
China: Big on numbers, short on experience
With almost 3 million people in its military, the People's Republic of China has the world's largest fighting force in terms of sheer manpower, but most of that won't come into play in any Pacific conflict. And analysts say manpower plays into one of China's biggest weakness: The collective lack of combat experience in those forces.
China has not fought a conflict since a border war with Vietnam in 1979; the US military, their most likely adversary, has been involved numerous conflicts over those 38 years.
"The US and its allies still have a significant edge for now in combat experience and logistical operations," Corey Wallace, a security analyst at Freie University in Berlin, said in an email to CNN. "The longer any conflict goes on, the greater the advantage for US and its allies."
China would also be hampered by its relative isolation, lacking allies and a network of bases in the region, Wallace said.
"It does restrain its ability to project power," Wallace said.
The Chinese navy also has only one active aircraft carrier, the Liaoning, which China bought from Ukraine in 1998, then rebuilt and commissioned in 2012 as a training vessel. In contrast, the US Navy has 10 aircraft carriers in its fleet, including one, the USS Ronald Reagan, based in Japan.
China's main strength lies in its extensive missile program, which features missiles that could hit US air bases in Japan and Guam, experts say.
If the US air bases can be taken out, the US' technologically superior F-35 and F-22 stealth fighters, and its B-1 and B-52 heavy bombers would be low on options to rearm and refuel.
A 2016 report from the U.S.-China Economic and Security Review Commission said China's DF-26 intermediate-range ballistic missile -- dubbed by analysts the "Guam killer" -- allows China to bring unprecedented firepower to bear on Guam, home to the US' vital Andersen Air Force Base.
China also boasts newly developed air-launched, land-attack cruise missiles which can be fired by its fleet of 36 H-6K long-range bombers. US military's crescent of technology
In any Western Pacific conflict, the US military possesses a network of bases where it can position fighting machines technologically superior to what any potential adversary can offer.
Those US and allied bases stretch from Misawa Air Base in the north of Japan to installations in Singapore regularly used by US forces. And the US has been positioning some of its newest and most sophisticated weapons at those bases -- F-35 stealth fighters, Advanced Hawkeye radar aircraft and Aegis warships in Japan, a littoral combat ship with helicopter drones in Singapore, F-22 stealth fighters in Australia.
The sheer breadth of it makes it hard to defeat.
"Their positioning is such that a simple attack on Japan will not be enough to permanently destabilize the US operating capacity in the region," Wallace said. "Neutralizing all of these installations will also require picking a lot more fights with a lot more actors."
That crescent of technology also makes any imminent US conflict with China unlikely, Wayne Mapp, a former New Zealand defense minister, told CNN.
"It's way too early for them to really test US power," Mapp said of Beijing.
"No part of the Chinese military is equal to the US military."
That said, the US does have its vulnerabilities. One of the biggest could be its reliance on aerial refueling and intelligence and surveillance aircraft, analysts say.
Long-range air-to-air missiles fired from jets such as China's new J-20 stealth fighter could knock down unarmed US support jets like KC-135 tankers and E-3A AWACS radar planes.
"Long-range air intercept weapons — coupled with the right fighter — could cut the sinews that allow the United States to conduct sustained air operations," defense editor Dave Majumdar wrote on The National Interest late last year.
Some analysts say the US Navy's aircraft carriers could be a vulnerability as they present large targets and a hit on one could provide a large boost to any adversary's morale.
But Wallace, the security expert, disagrees, saying the US has decades of experience on how to use and protect them.
"I'm not convinced they are the sitting ducks many regard them to be -- especially compared to fixed bases," he said.
Strikes on those fixed bases could result in devastating casualties to the US military. According to the International Institute for Strategic Studies, the US has more than 47,000 troops stationed in Japan, more than 28,000 in South Korea, 5,000 in Guam and hundreds of other scattered among Pacific allies such as Singapore and Australia. North Korea keeps everyone guessing
What makes Pyongyang strong? Two things: Kim Jong Un has nuclear capability and no adversary can be sure if he'll use it.
Pyongyang says it successfully tested a nuclear warhead last year. This year missiles it tested fell just 200 miles from the Japanese coast.
That has kept leaders in Washington, Tokyo and Seoul guessing as to what Kim will do next, and wary of any pre-emptive strike.
"It does make them immune to invasion," Mapp, the former New Zealand defense minister, says.
The rouge state does have another key advantage -- the South Korean capital of Seoul is only 35 miles from the border with the North, putting 25 million people there within range of North Korean artillery and rockets and the lead elements of Pyongyang's military of 1.2 million members, just 100,000 shy of the entire size of the US military.
North Korea also has a sizeable tank force of up to 4,200, according to some estimates, but none are believed to be a match for South Korean tanks, which while they number roughly half of the North Korean force, are decades ahead in technology.
Pyongyang's primary disadvantage comes immediately after any first strike. The country is resource poor and in no position to engage in sustained combat with the US, South Korean and possibly Japanese militaries.
North Korea has also put itself in a difficult position with long-time ally China. Beijing has called on Pyongyang to stop the weapons tests which have ratcheted up tensions in East Asia.
The injection of the US' THAAD anti-missile system into South Korea in response to Pyongyang's missile tests has angered Beijing, which sees THAAD as damaging its overall security interests.
"(China) may have tolerated a lot from (North Korea) to ensure stability on its borders and a buffer between itself and US forces," said Wallace. "If the DPRK [Democratic People's Republic of North Korea] is seen to be working against Chinese security interests, as it arguably is right now, then it might change these calculations." South Korea's ability to focus
Seoul has been facing a hostile North Korea since the Korean War armistice in 1953. That, said Mapp, is a key strength, one which has enabled Seoul to develop a formidable military focused on only one thing: not attacking someone else, but protecting themselves.
The International Institute for Strategic Studies points out that Seoul has procured or will get advanced weaponry; these include cruise missiles for its F-15 fighters, a fleet of F-35 stealth fighters, new submarines and more Sejong the Great-class guided-missile destroyers, already considered among the world's most-advanced warships.
In fact, the number of South Korea large surface ships -- frigates and destroyers -- outnumbers North Korea's fleet 23 to 3, according to globalfirepower.com.
That's a lot of firepower that would be directed at North Korea, but experts say Seoul doesn't have to worry about anything else because those worries are Washington's.
"South Korea's strength is the United States. They (South Korea) really don't do anything else; they only have to worry about" North Korea, Mapp said.
But Wallace says it's another alliance that may prove to be a South Korean vulnerability in the event of conflict.
South Korea doesn't "play nice with Japan on a variety of military and intelligence issues," he says.
Evidence of that may be in the Aegis missile defense system, deployed on South Korean and Japanese warships.
South Korean Aegis ships cannot share timely missile intercept information with their Japanese counterparts because Seoul and Tokyo can't agree on a data encryption system that works between them, said Carl Schuster, a Hawaii Pacific University professor and former director of operations at the US Pacific Command's Joint Intelligence Center.
South Korea seems to be taking steps to address that issue, however. This week a South Korean Aegis destroyer was practicing missiles intercepts with Japanese and US destroyers equipped with the Aegis missile defense system. The trilateral tests were the third in a series aimed at boosting missile defense cooperation among the three allies, US Navy 7th Fleet spokesman Lt. Paul Newell said.
Japan can't punch back
While South Korea needs to only concentrate on one adversary, Japan needs to focus on two, North Korea and China.
North Korea's missiles that fell in waters off Japan last week brought new fears in Tokyo as to what might come next from the Kim regime. North Korea said the tests were carried out by the military unit tasked with taking on US military bases in Japan.
And Japan and China have locked horns over the Senkaku Islands, the Tokyo-administered chain claimed by Beijing, which refers to them as the Diaoyu Islands.
In regards to China, Wallace identifies Japan's anti-submarine warfare capabilities as key.
Resurgent Japan military 'can stand toe to toe with anybody'
"Subsurface detection and reaction is a Japanese strength in both technological and operational terms, and a Chinese weakness, even if (China) quantitatively has a larger subsurface fleet," Wallace said.
Japan's Soryu-class hunter-killer subs are a big part of that strength. Tokyo has 12 of the Soryu-class, the largest subs it has built since World War II, in service or on order, according to the International Institute for Strategic Studies.
Analysts say the Soryus are stealthy and can operate effectively close to the seabed, giving them an advantage over a Chinese submarine fleet numbering around 70 vessels, according to experts.
The Soryu-class subs become more formidable combined with Japan's helicopter carriers and sub-hunting aircraft and a surprisingly long history of using them, Wallace said, "even helping the US keep the Soviet Pacific subsurface fleet bottled up in the North (Pacific) during the Cold War."
Japan's big weakness is its ability to project offensive firepower, analysts say.
"They can bomb anyone landing on one of Japan's main islands... but they can't strike Chinese or North Korean air bases or missile sites," Schuster says, pointing out that Japanese warplanes don't carry the equipment necessary to suppress enemy air defenses.
"They can defend but they can't punch back," he says.