Japan's Nikkei Retreats as Us-iran Ceasefire Optimism Fades

Japan's Nikkei share average retreated on Thursday after a sharp rally in the previous session, as initial euphoria over a two-week fragile ceasefire in the Middle East gave way to a more cautious market outlook.

Investor sentiment weakened after Israel launched its heaviest strikes yet on Lebanon on Wednesday, killing hundreds of people and prompting threats of retaliation from Iran. Tehran also signalled it would be "unreasonable" to continue negotiations for a permanent peace deal with the United States.

The Nikkei .N225 was down 0.55% at 55,997.18, at the end of the morning session, and on track to snap a fourth-session rally, if the current trend persisted.

The broader Topix .TOPX slipped 0.76% at 3,746.68.

Nikkei 225 Futures on the Chicago Mercantile Exchange NIYcm1 crossed the 57,000 level overnight.

In the previous session, the Nikkei surged 5.4% to its highest point in more than one month on hopes the Strait of Hormuz would reopen after U.S. President Donald Trump agreed to a two-week ceasefire with Iran.

The six‑week conflict had brought traffic through the strait, a chokepoint for about 20% of global oil and liquefied natural gas shipments, close to a standstill, pushing global energy prices sharply higher.

"Investors have turned calm and started thinking if the peace talks will really work," said Takamasa Ikeda, senior portfolio manager at GCI Asset Management.

"Oil prices rose again, and that weighed on the equities market."

Chipmakers and artificial intelligence-related shares slipped, with Advantest 6857.T and SoftBank Group 9984.T down 2.06%% and 3.3%, respectively.

Shares of Fast Retailing 9983.T, the parent company of Uniqlo, rose 0.84% ahead of the retailer's earnings, becoming the biggest support for the Nikkei.

Of more than 1,600 stocks trading on the Tokyo Stock Exchange's prime market, 24% rose, 72% declined, and 2% traded flat.