Taiwan and Korea were legally Japanese territories under the Japanese empire. When Japan began its imperial project, there were two basic models for imperialism: the British and the French. The British paradigm treated these colonial areas as dependencies of the crown with various levels of autonomy. The French form of empire was predicated upon treating colonial territory as a zone that could be turned into a part of France. After much debate within the imperial government, the Japanese opted for the French model between 1910-15. Like the French colony in Algeria, Korea and Taiwan were administratively linked to the metropole and governed as if they were part of Japan. Both Taiwan and Korea were subdivided into prefectures and its inhabitants had the legal rights and responsibilities of Japanese citizens, with the imperial government emphasizing responsibilities like conscription and hewing to a program of cultural assimilation that transgressed the rights of Taiwanese and Koreans. Additionally, the Japanese government did encourage settlement of these areas by Japanese and the state supported Japanese business investment in Korea and Taiwan.

However, even though these were new Japanese prefectures, the Japanese governmental circles still saw these areas in highly functional terms. Both Korea and Taiwan had to serve Japanese imperial interests and not vice-versa. There Japanese placed a priority on the development of heavy industry and mineral extraction that would help make Japan self-sufficient. Agricultural development was also geared towards export to the home islands. This was part of the reason why the 1944-45 and the immediate postwar period was an era of great hunger for Japan, it had lost access to a major source of its food. To be fair to the Japanese, they were far from alone in this imperial exploitation and its empire was comparatively more humane than its contemporaries (indices like Korean life expectancy and literacy went up, unlike British India). Koreans drafted into the Japanese military tended to do the drudge work and Japanese companies operating within these areas were quite exploitative. The bureaucracy and other imperial structures favored Japanese settlers over the natives. Even when Japanese imperial officials tacked to a pan-Asian course, they placed Japan first in its brotherhood of East Asia.

So, in a roundabout answer to the OP's question, after ca. 1915, the Japanese government really did not distinguish between these areas being new provinces and its exploitation of these areas.

Sources

Beasley, W. G. Japanese Imperialism, 1894-1945. Oxford [Oxfordshire]: Clarendon Press, 1987.

Duus, Peter. The Abacus and the Sword The Japanese Penetration of Korea, 1895-1910. Berkeley: University of California Press, 1995.

Myers, Ramon Hawley, Mark R. Peattie, and Jingzhi Zhen. The Japanese colonial empire, 1895-1945. Princeton, N.J.: Princeton University Press, 1984.

Manchuria was a satellite state, not an overseas possession. Many Japanese settled there, in Manchuria's case starting when it was still part of China. But the question of colonies vs new provinces is one of interpretation - the Japanese weren't inclined to speak of what they were doing as colonialism - and the way you phrase it makes it seem like a distinction without a difference.