China's two biggest memory chipmakers have quietly bought enough Dutch chipmaking machines to cover three years of expansion, a defensive move that shows how much they still depend on ASML.

• CXMT and YMTC have stockpiled ASML's older DUV machines, enough to keep building factories for three years.
• They are racing ahead of possible new US rules that would block DUV sales and even repair service to China.
• China cannot buy ASML's most advanced EUV machines at all, so DUV is the best gear it can get.
• A Shanghai state-backed rival is trying to build its own DUV machines, aiming for a dozen by year end and 20 by the end of 2027, but chipmakers still prefer ASML's.
• China is thought to be about a decade behind on EUV, though closer on DUV, and some firms are working out how to make advanced chips without the newest machines.

Outlook: Expect Washington to keep tightening the screws on DUV exports and servicing, while China buys and builds as fast as it can before the door shuts.