Well, number one is impossible. Great Britain was the first country to industrialize; they started the Industrial Revolution in 1780, with it taking full force in 1840. Japan's industrialization happened with the Meiji Restoration, a full 30 years after the formal beginning of the British industrialization.
2) Literally no one ever conquered Japan. Ask the Mongols- they tried. twice. and failed. twice.
3)Japan only has 20% arable land, so that's not much. And even still, the only country they actually traded with until after their industrialization was the Netherlands.
4) Japan, only a couple hundred miles from China, borrowed many aspect of their culture, which explains why Buddhism played (and still does to an extent) a large role in Japanese society.
So #4 is your answer