Harrington carded a six-under-par 66 for an 11-under halfway total, two behind Strange (65) and one behind Japan's Azuma Yano (65), Brazilian Lucas Lee (67) and Australian Terry Pilkadaris (64).
A total of 36 players will return on Saturday to the Greg Norman-designed course to complete their second round in the $1 million event, co-sanctioned by the Japan Golf Tour Organisation and OneAsia.
Harrington said he had finally found the perfect pair of glasses as he compiled a bogey-free round at the Thana City Golf & Sports Club.
"These glasses are pair number five. I also have six and seven with me this week, but pair number five seems to be the one making it at the moment," the world number 54 said on the official website (www.oneasia.asia).
"They're all different frames and different lenses. These are a little bit shorter and the screw is a bit long, but they seem to be winning."
Defending champion Chris Wood finished the day level with Harrington and after reaching the turn with a cold putter a glance at the leaderboard was all he needed to kick start his round, posting five birdies on the closing nine.
"I was looking at the leaderboard and using that as motivation, because you've obviously got someone like Harrington, who'll take some chasing, but all the top players on the Japan and OneAsia Tours as well," said the Englishman.
Strange, who lost his European Tour card last year, said the opportunity to play closer to home and spend more time with his family has helped him improve his game.
"A few things have changed in my life," he said. "I'm not playing as much overseas, and we've got another daughter so I'm trying to be home a bit more. The mind is relaxed and refreshed.
"I think the Japanese Tour is a great fit -- especially for family life in Australia. You're not flying to Europe for six or seven months of the year and then coming back, so if I'm fortunate enough to win this week, I'll be in Japan and that would be great."
Supremely confident Thai youngster Thanyakon Khrongpha was the star of the day as he equalled the course record 63, set by Welshman Ian Woosnam in 1996.
"I am starting to think about winning the tournament now as there are going to be a lot of low scores and I have to be aggressive," said the 22-year-old, who turned pro two years ago.
Ireland's Paul McGinley, who will lead Europe in the Ryder Cup against the United States next year, was forced to withdraw midway through the second round with a bad back. (Reporting by Sudipto Ganguly in Mumbai; editing by Tom Pilcher)