China's calculation was that it had nothing to lose from political propaganda. The US also decided to sell subs, one of the weapons to which China strongly objects. This can be seen as a rewarding outcome for Taiwan. China has changed the focus of its naval strategy from coastal defense to offshore defense. It continues to strengthen its naval power and is eager to extend it over the island chain of the Aleutians, Kuriles, Japanese archipelago, Ryukyus, Taiwan, the Philippines and the Great Sunda islands.
China has a large submarine fleet and South Korea, Malaysia and Singapore have also bought subs.
Taiwan's acquisition of submarines is thus legitimate in defense terms. Because of the low risk involved in submarine purchases, Taiwan once listed them as a priority. It took Taiwan more than 10 years to secure F-16 fighters and 20 years to get subs, both of which are the result of its unique political environment. According to the Taiwan Relations Act, the US is to sell only defensive weapons to Taiwan. In the past, the US described submarines as offensive weapons and held firm on not selling them.