Taiwan is fighting a quiet war to keep its chip engineers and technology from leaking to China, and the scale of the problem is bigger than most people realize.

• Taiwanese investigators have looked into 166 cases over six years of Chinese firms operating illegally on the island or poaching tech workers, plus dozens of trade-secret cases.
• Chinese companies hide behind shell firms, foreign investment structures, and non-Chinese figureheads — one engineer worked for what he thought was a US employer, only to find his daily contacts were all in Nanjing.
• The lure is money: Chinese firms offer five times Taiwanese pay, sometimes ten times.
• Big names are caught up in it, including Xiaomi, OnePlus, and chipmaker SMIC, which allegedly registered in Taiwan as a Samoan company.
• Taiwan makes over 60% of the world's chips and about 90% of the most advanced ones, so the stakes are national security, not just business.

Outlook: Expect more raids and prosecutions as Taiwan tightens its rules, while China — still years behind on the most advanced chips — keeps looking for ways in.