Chawrasia shot two-under-par 70 in the first round and sharing the place at T5 with those bunched in fifth following matching rounds of 70s at the US$850,000 event.
Harding, the first player to win consecutive events on the Asian Tour this season, fired one eagle and four birdies against two bogeys to take his share of place atop the leaderboard at the fabled Taiwan Golf and Country Club, which is celebrating its centennial year in 2018.
Australian Maverick Antcliff trails the leading trio by one shot in fourth place while local hero Lin Wen-tang, Indian hotshot S.S.P. Chawrasia and Chinese ace Liang Wen-chong were one shot behind sharing the fifth place.
Starting from the par-three 10th hole, the 32-year-old Harding sank two birdies against a bogey to turn in 35. He fired another two birdies and an eagle on the par-five seventh before dropping a shot on his last hole ninth.
Tabuena, who came close to winning the storied event before settling for second place in 2016, renewed his love affair with the Tamsui course after marking his card with five birdies against a bogey. He is chasing for his second Asian Tour victory in a country where he had finished second on four different occasions.
Weber rediscovered some of his best form after closing with two straight birdies to grab a share of the lead. Placed 96th on the latest Asian Tour Habitat for Humanity Standings, the 28-year-old Weber needs a strong performance this week to possibly break into top-60 and retain his card for the 2019 season.