A One Person Bidding War

After a short pause, Top eBay Chess Items by Price returns to the artwork category last seen in Chess of the Gentry and Military. The painting below, titled 'Carlo Canevari Oil on Board of Chess Game Lot 1251', subtitled 'Part of a live auction event on Sunday, Feb 15', sold for US $2200 after 16 bids from a single bidder.

Not understanding what could trigger that bidding scenario, I looked at the bidding history. The period covered by the bidding lasted less than a minute with the bid starting at $1000, incrementing by $100 every few seconds, and ending at the price shown. It must be a bidding strategy peculiar to live auctions.

The description was also unusual. About the art itself, it added only

Seller's Estimate: USD 300.00 - 600.00 • 12" x 8.25" including frame. Signed lower right: Carlo Canevari.

followed by detailed payment and shipping instructions. Another auction, from Christies.com, informs, 'Carlo Canevari (Italian, 1922-1996)'. Is that a porthole near the top of the painting?