Credit: © pixelshot via Canva.com China has imposed a cash deposit of up to 99.2% on imports of a Japanese chemical that chip fabs use to build the films inside logic and memory chips. The rate is close to prohibitive. It took effect on Tuesday. China’s Ministry of Commerce published the preliminary determination on 7 September as Announcement No. 37 of 2026.
Chan Ho-Him and Mari Yamaguchi reported the ruling and Tokyo’s response for the Associated Press, which describes Japan as the leading producer of ultrapure dichlorosilane for chip fabrication. What the ruling says The published rates are not uniform. Shin-Etsu Chemical draws 99.2%. Denal Silane, a joint venture between Denka and Air Liquide, draws 80.8%.
Every other Japanese exporter draws 99.2%. So the largest supplier gets the top rate, and so does anyone who might replace it. Dichlorosilane, known in fabs as DCS, feeds chemical vapour deposition. It lays down silicon and oxide films a few atoms thick, layer after layer, in both logic and memory production.
It is not exotic. It is a working gas, consumed continuously, and a fab that cannot get it cannot run. The measure is provisional. The ministry opened the investigation on 7 January, and interested parties have ten days to comment before a final ruling.
One number we cannot give you is Japan’s share of world supply. The figures circulating in market-research summaries contradict each other badly, ranging from under a tenth to three quarters, and none of them cites a primary source. So we are using AP’s wording rather than inventing precision: Japan leads, in a market it calls highly competitive. This is trade law, not an export control Here is the part worth noticing.
Beijing has spent two years restricting materials through export controls: gallium, germanium, graphite, rare earths. It also placed curbs on 56 US firms in June. Those measures are unmistakable acts of policy, and they invite retaliation precisely because everyone can see what they are. An anti-dumping duty looks like something else.
It is a trade remedy recognised under WTO rules, available to any member whose domestic producers claim injury from underpriced imports. It comes with a petitioner, an investigation, a determination and a comment period. The European Union used the same instrument against Chinese electric vehicles. And it produces the same result.
A 99.2% deposit at customs stops the goods as effectively as a licence requirement, while looking like ordinary trade defence rather than statecraft. The dates are worth reading in order Tangshan Sunfar Electronic Materials, a Chinese producer, filed the application on 8 December 2025. Prime Minister Sanae Takaichi had suggested in November that Japan’s military could intervene in a Taiwan contingency. Relations have been strained since, and Beijing has imposed dual-use export controls on Japanese firms in the months that followed.
We cannot show that one caused the other, and we will not imply it. Anti-dumping petitions take months to prepare, and this one may have been under way before the remarks. What we can say is that it arrived roughly a month after them, and that the determination landed while the dispute was still live. Chief Cabinet Secretary Minoru Kihara lodged a protest and said Tokyo would respond appropriately.
The people this hurts most are in China A duty on imports raises the price for the importer. Chinese fabs are the ones buying Japanese DCS, and Chinese memory makers are among the heaviest users, because memory stacks far more deposited layers than logic does. CXMT, the country’s largest DRAM producer, is already fighting a US listing in the Washington courts. Its input costs now rise by order of its own government.
That is not an accident. It is what a protective duty is for. Tangshan Sunfar wants the Chinese market, and the ruling hands it over at a price Japanese exporters cannot meet. Whether Chinese DCS is good enough is a separate question, and the word ultrapure is doing real work in that sentence.
Deposition chemistry is unforgiving about contamination, and a fab that switches supplier buys months of qualification work. Europe buys the chips, not the gas Memory prices are the transmission channel. European desktop shipments are already falling because buyers ran out of money, with DRAM up sharply over three quarters. Anything that raises the cost of making memory in China reaches European buyers eventually, through the price of a finished module rather than any shortage of gas.
The reverse effect is also possible and gets less attention. Japanese producers shut out of China have volume to place somewhere. That could make DCS cheaper for fabs in Europe, Taiwan and the United States. Nobody has published numbers on it, so we are raising it as a question rather than a forecast.
Three choke points in one day This is the third materials story we have written today, and the pattern is the point. IQE’s chief executive warned that China holds 70% of indium phosphide, the compound underneath the photonics in AI data centres. The Financial Times reported that China’s domestic answer to ASML still runs on Zeiss lenses, a dependency pointing the other way. Now a deposition gas, restricted through trade law.
Different materials, different directions, different legal instruments. What they share is that the contest has moved off finished chips and onto the inputs, where dependencies are older, far less visible, and much harder to substitute in a hurry. What to watch Whether the final determination holds the rates. Provisional deposits are refundable if the final ruling goes the other way, which makes this reversible, and therefore usable as leverage rather than as a wall.
Whether Tokyo files at the WTO. Respond appropriately is the phrasing a government reaches for before it has decided. And whether Chinese fabs report input trouble. That is the number that will show whether Beijing accepted a real cost here, or already had a domestic substitute standing by.
