https://quadrant.org.au/magazine/2022/11/how-xi-misreads-the-taiwan-battlefield/
In any war between China on the one hand and Taiwan, Japan, the US and their allies on the other, Chinese vessels of all kinds will be prevented from significant access to the Pacific Ocean. The Chinese (and Russian) Pacific fleets will almost certainly be enclosed in their coastal waters.
This is because the First Island Chain running parallel to the mainland from Sakhalin Island in the north down through Japan, the Ryukyu islands, Taiwan, and on to the Philippine Islands and Indonesia, is a natural barrier now being fortified by the Japanese and Taiwanese militaries and the US Marines. The Commander of the US Marine Corps, General David Berger, recently announced that the Marines were changing their policies and missions in reaction to developments in Asia. He said a “new mission” for the Marines would be “island hopping” in the Indo-Pacific armed with anti-ship missiles to meet the growing China threat. (see The Times, London dispatch, Weekend Australian 6-7/11/21). Presumably, they would carry Tomahawk anti-ship missiles and be supported by US specifically designed shallow-hulled coastal patrol vessels, armed with the same Tomahawks, as well as Japanese submarines.
This would make transit through the Chain almost impossible for hostile surface ships and submarines. One of the difficulties for Chinese and Russian submarines is the difference between the relatively shallow waters of the seas between mainland China and the First Island Chain and the vast depths and trenches of the Pacific Ocean east of the Chain. Submarines would have to surface or near surface to transit the Chain either way, making them easily detectable and vulnerable.
Furthermore, at the southern end of the Chain, other US forces along with the navies of Australia, France, Britain and hopefully India and Indonesia could block Chinese and Russian naval and merchant shipping transiting the Malacca Strait and contiguous Indonesian waterways and passages. As a result, China could suffer a serious trade blockade.
As I argued in an earlier article in Quadrant (April 2021), Taiwan is a key link in the First Island Chain and its conquest by China would constitute an existential threat to Japan. Over many decades Japan has sought to preserve and strengthen the Chain as a protective instrument. If China took control of Taiwan it would gain access to the North Pacific and be able to surround Japan, which is a nation lacking geographical strategic depth. A China attack on Taiwan would lead to a Third Sino-Japanese War and the US would be obliged to support Japan (and therefore Taiwan) under the US-Japan Mutual Defense and Security Treaty. China’s recent threats to Taiwan have led to Japan announcing it would double its defence expenditure and invest heavily in new technology including robots and drones. Twenty years ago, China openly and seriously threatened Taiwan and, as a result, Japan immediately intensified its pressure on the US, imploring it to provide ABM (anti-ballistic missile) protection against China with the latest in US technology. The result was the 2004 US-Japan ABM Agreement which presumably also covered Taiwan (see below).
While many of us were discussing the possibilities of the “looming war over Taiwan”, the AUKUS agreement was announced on September 16, 2021. The major aspect of this agreement was the decision by the US, the UK and Australia to build at least eight nuclear-powered submarines (SSNs) for Australia. Initially, nothing much else was mentioned, at least not in the press.
