Tokyo's Nikkei was up 1.2 percent in the morning session after the US announced a first tranche of investments by Japan out of a colossal $550 billion promised by Tokyo in its trade deal with President Donald Trump.

But the holiday period meant that trading floors were shut in Hong Kong, Shanghai, Seoul and Taipei. Sydney was marginally up.

West Texas Intermediate was up 0.1 percent at $62.38 per barrel, while Brent also rose 0.1 percent to $67.49.

Oil prices had dropped Tuesday as Iran appeared upbeat after talks with US officials.

That followed an earlier rise when Trump ramped up threats towards Iran, a large crude producer, but Iranian Foreign Minister Abbas Araghchi said "a new window of opportunity has opened".

"We are hopeful that negotiation will lead to a sustainable and negotiated solution," he said, though he added that "Iran remains fully prepared to defend itself against any threat or act of aggression".

The announcement on the first round of investments by Japan detailed commitments of $36 billion for three infrastructure projects and came as the country comes under pressure to deliver on its pledges made in 2025 in return for lower US trade tariffs.

"Investors are likely to focus on Japanese companies tied to gas-fired power generation, crude oil exports, and synthetic diamonds," sectors targeted by these initial US investments, noted analysts at Tokai Tokyo Intelligence.

Traders are also keeping an eye on artificial intelligence this week, as tech CEOs and global leaders rub shoulders at the AI Impact Summit in New Delhi.

Touted as the biggest edition yet, the five-day summit aims to declare a "shared roadmap for global AI governance and collaboration".

While frenzied demand for generative AI has turbocharged profits for many tech companies, anxiety is growing over the risks that it poses to society and the environment.

- Key figures at around 0230 GMT -

Tokyo - Nikkei 225: UP 1.2 percent at 57,253.46

Hong Kong - Hang Seng Index: closed for holiday

Shanghai - Composite: closed for holiday

Dollar/yen: UP at 153.56 yen from 153.29 yen on Monday

Euro/dollar: DOWN at $1.1845 from $1.1854

Pound/dollar: DOWN at $1.3556 from $1.3568

Euro/pound: UP at 87.38 from 87.37 pence

West Texas Intermediate: UP 0.1 percent at $62.38 per barrel

Brent North Sea Crude: UP 0.1 percent at $67.49 per barrel

New York - Dow: UP 0.1 percent at 49,533.19 points (close)

London - FTSE 100: UP 0.8 percent at at 10,556.17 (close)