The benchmark Nikkei 225 index inched down 0.03 percent, or 11.60 points, to end at 40,097.63, while the broader Topix index climbed 0.50 percent, or 13.65 points, to 2,719.93.

The Nikkei index temporarily dropped “following reports that the US government is working to block exports of AI semiconductors to China… amid a sense of short-term overheating” of Tokyo shares, IwaiCosmo Securities said.

While many investors expect the Nikkei to gain further, they are also aware of the short-term risks of overheating after recent rallies pushed the headline index above the 40,000 mark on Monday for the first time.

Market players are awaiting economic indicators and events this week, including US jobs data, congressional testimony from Federal Reserve Chair Jerome Powell, President Joe Biden’s State of the Union address and a European Central Bank decision.

The dollar fetched 150.54 yen against 150.51 yen in New York on Monday.

Among major shares, chip-testing equipment maker Advantest tumbled 2.64 percent to 7,185 yen while electronic parts maker Murata Manufacturing, which produces chips, slipped 0.56 percent to 3,005 yen.

Chip-making equipment manufacturer Tokyo Electron, which jumped more than two percent on Monday, added 0.41 percent to 39,450 yen.