Policies on admission low-skilled workers in Korea, Japan and Taiwan (China): Similarities and differences

Unlike Taiwan (China) both Japan and Korea have long-standing policies which eschew the admission of low-skilled labour from abroad. What prompted them to abandon or make exceptions to the policy? Having opened their gates to low-skilled foreign workers, what policies and programmes did the three countries adopt to address concerns over the likelihood of permanent stay, proble s with social integration and possible negative impact on wages of native workers?