A little-known Japanese chemical maker has become one of the hardest-to-replace links in the global chip supply chain, and Taiwan's chipmakers are pulling it even closer.

• Tokyo Ohka Kogyo makes photoresist, the light-sensitive coating that lets chip circuits be printed onto wafers, and holds about a quarter of the world market — first place globally.
• With just over 2,000 staff, it earned record profits last year as sales of advanced EUV and ArF materials jumped, and Intel has called it a strategic leading-edge supplier.
• Its real moat is setting the rules: a developer concentration it introduced in the 1970s became the worldwide standard that most photoresists are still designed around.
• Japanese firms together control roughly 80% of this market, giving Tokyo a quiet chokehold over who can make advanced chips.
• Rival JSR is building its first Taiwan production plant, reportedly at TSMC's request, while Tokyo Ohka has reshuffled its own Taiwan operations toward local service and high-end work.

Outlook: As chip processes get smaller, material suppliers will keep moving production next to Taiwan's fabs, deepening the tie between Japanese chemicals and Taiwanese chipmaking.