Japan's Nikkei tumbles to 6-1/2-month low as US tariff jitters weigh

TOKYO, March 31 (Reuters) - Japan's Nikkei share average tumbled on Monday to its lowest point in more than six months, following sharp losses on Wall Street in the previous session, as investors assessed the risk of imminent U.S. trade tariffs.

As of 0130 GMT, the Nikkei .N225 was down 3.5% at 35,810.28. Earlier in the session, the index dropped to 35,574.61, its lowest level since September 11.

The broader Topix .TOPX fell 3% to 2,671.83.

"Investors' sentiment was weakened as there is so much uncertainty ahead of the announcement of reciprocal tariffs," said Hiroyuki Ueno, chief strategist at Sumitomo Mitsui Trust Asset Management.

"They were in a risk-off mode and offloaded what they had bought. But this week is the toughest, and they will start buying them back once the outlook becomes clear."

U.S. President Donald Trump has promised to unveil a massive tariff plan on Wednesday, which he has dubbed "Liberation Day." He has already imposed tariffs on aluminum, steel and autos, along with increased tariffs on all goods from China.

Trump said on Sunday reciprocal tariffs that he is set to announce will include all nations, not just a smaller group of 10 to 15 countries with the biggest trade imbalances.

In Japan, Uniqlo-brand owner Fast Retailing 9983.T lost 3.6% while chip-related Tokyo Electron 8035.T and Advantest 6857.T slipped 5.7% and 6.2%, respectively.

Shares of Mitsubishi UFJ Financial Group 8306.T and Sumitomo Mitsui Financial Group 8316.T lost 3.9% and 3.3%, respectively.

Automakers fell, with Toyota Motor 7203.T and Honda Motor 7267.T losing 2.7% and 3%, respectively.

All of the Tokyo Stock Exchange's 33 industry sub-indexes fell, with the insurance sector .IINSU.T lost 4.6%.

The Nikkei volatility index .JNIV jumped 5 points to 27.4 to its highest level since March 11.

All but one of 225 components of the Nikkei index fell, with chipmaker Renesas Electronics 6723.T tanking 8.7%.