How China is advancing its military reach
As the US shifts its focus to Asia, Alexander Neill, head of the Asia Security Programme at the Royal United Services Institute, sets out the Chinese military advances challenging the regional balance.
At the Pentagon recently, US President Barack Obama announced deep cuts to the US military and set out a shift in attention towards the Asia-Pacific region, in a thinly-veiled message to China.
Despite a narrative of peaceful intent, China's leaders have struggled to reassure the US over the direction of the People's Liberation Army (PLA). Both countries admit that their military dialogue falls well behind other aspects of the relationship.
So the shift has brought renewed scrutiny of the PLA's latest capabilities against US dominance in the Pacific.
In recent years the PLA has demonstrated impressive new capabilities at sea and in space, aimed at showcasing the success of its modernisation effort.
The obvious message is to deliver a powerful warning if Taiwan were to declare formal independence.
But Pentagon planners are now concerned that the Taiwan contingency has been eclipsed by China's broader maritime territorial claims and demands for more international space to protect the arteries feeding China's growth.
China is developing a range of capabilities linked to the space and cyber domain in order to sidestep the overwhelming might of the US military in the Pacific region. The PLA calls this fighting "local wars under informationised conditions".
China recognised almost two decades ago that in the mid-term the PLA could be no match for US conventional forces. So it began working on what was dubbed "unrestricted warfare" - combining multiple methods to defeat a superior opponent.
At the same time party leaders launched adventurous civilian acquisition projects in the high-tech domain to increase Chinese competitiveness and to boost indigenous production capabilities.
The PLA has been running military projects mirroring these civilian acquisition ventures. Sometimes involving dual-use technologies, the military and civilian strands have often been indistinguishable.
China's space programme is a case in point. The recent successful docking manoeuvre between a Shenzhou module and the Tiangong Space station is as much a triumph for the PLA as it is for China's civilian space agency.
Should the US ever intervene in a cross-strait clash or challenge China's maritime claims, Beijing would employ a pre-emptive "sea denial" strategy alongside its conventional operations - preventing US battle carrier groups operating in or near its claimed territorial waters.
Its submarine-launched ballistic and cruise missiles are now a lethal force. China's long-range nuclear weapons systems have also undergone significant upgrades and its strategic rocket force, the Second Artillery Corps, is very much the pride of the PLA.
One of the most pressing concerns for the US navy is the threat posed by a "carrier killer" anti-ship missile with enhanced targeting capabilities facilitated from space. China very recently launched its own Beidou Positioning System, challenging the monopoly of the US Global Positioning System (GPS).
One of the PLA's most sensitive advances has been the secret deployment and testing of advanced anti-satellite (ASAT) and Anti Ballistic Missile (ABM) weapons systems.
Two years ago, China successfully intercepted one of its own ballistic missiles as it streaked through space. This test coincided with the Pentagon's sale of Ballistic Missile Defence (BMD) Patriot systems to Taiwan.
Some experts believe a Chinese ASAT campaign against a careful selected group of US satellites could have catastrophic effect on the US military.
This capability, combined with the potential for China to develop its own Ballistic Missile Defence umbrella, suggests that the space domain will be a new theatre for US-China rivalry.
Chinese ASAT capabilities are not exclusively reserved for "kill vehicles", like the one which obliterated an ageing Chinese weather satellite in 2007.
It is now believed that the successful 2007 "kill" was in fact the third test in a series. Previous tests had demonstrated an ability to manoeuvre in proximity to targeted satellites.
This would suggest that China has experimented with techniques which could be used for "space mining", where mines or mini-satellites armed with jamming technologies could be placed within the orbits of an opponent's spacecraft.
In addition to its "sea denial" and space warfare strategies, China is also expanding its conventional capabilities.
The PLA Air Force in recent years has extended its ability for offshore operations, enhancing an offensive capability. It is planning an overhaul of its ageing fleet with the deployment of over 3,000 new aircraft.
For the most part China has relied on copying Russian fighter technology. However, the roll-out of the Chengdu J-20 Stealth fighter prototype raised eyebrows last year, carefully timed to coincide with a visit by the US defence secretary.
There have been some very significant developments in the deployment of Chinese submarines in recent years. Beijing possesses 10 Russian-built ultra-quiet Kilo class submarines possibly armed with 200km-range anti-ship cruise missiles.
Since 2006, when a Chinese submarine surfaced undetected within torpedo range of the US aircraft carrier USS Kitty Hawk, China's submarine force has regularly marauded the US Navy and its allies in the Pacific.
It is thought that China plans to build three aircraft carrier battle groups, each armed with 40 fighters, up to eight warships, three nuclear-powered attack submarines and a number of support vessels. The PLA Navy's retrofitted Varyag carrier, currently under sea-trials, will serve as a training platform.
Even if the aircraft carrier would likely be a prestige piece and more directed at Chinese domestic pride, the prospect of a Chinese aircraft carrier will certainly cause ripples for the broader East Asian naval balance.
While much attention has been paid to the breakneck speed of Chinese military modernisation over the last decade, the events of 9/11 and the subsequent campaigns in the Middle East and Afghanistan provided a window of opportunity for China to accelerate development.
In some cases there may have been, quite literally, windfalls for the PLA. There is speculation that China acquired undamaged Tomahawk cruise missile components in the early stages of the Afghanistan campaign a decade ago.
When US special forces failed to completely destroy one of their stealth helicopters during Operation Geronimo, Pakistan's military may have allowed PLA counterparts to inspect the tail rotor.
The PLA must be congratulating itself on the impressive array of weaponry which has tilted the balance in the Taiwan Strait in its favour.
China's new-found capabilities combined with the opaque nature of its military modernisation create a formula for mistrust with the US.
There are perhaps three factors for uncertainty. Firstly, the Chinese military's confidence in its new equipment could lead to an overestimation of its capability as an emerging great power.
Secondly, the Chinese leadership could underestimate its ability to control an unexpected escalation of hostilities in the Pacific.
Finally, the domestic political factor - the PLA's external behaviour could become a reaction to internal nationalistic sentiment, instability or faction fighting as Beijing prepares for the fifth generation leadership handover this year.