A rare Jichimu horseshoe back armchair, (quanyi) Qing Dynasty, late 17th / 18th Century

the five-member curved toprail supported by long slender side posts continuing down to join the front posts at the 'pipe-joints', set with an undecorated backsplat with characteristic feathery grain flanked by the upper extensions of the rear legs forming the rear corner posts above the rectangular seat frame enclosing the original soft cane mat above legs joined by stepped stretchers and straight beaded aprons with long spandrels

The Mr. and Mrs. Robert Piccus Collection.
Christie's New York, 18th September 1997, lot 49.
M.D. Flacks, Ltd., New York. 

Curtis Evarts, 'Classical Chinese Furnture in the Piccus Collection,' JCCFS, Autumn 1992, p. 1992, p. 16, fig. 18 and 18a. 

The construction of the three-piece armrest is a rather unique variation of the half-lap pressure-peg joint with blind tenons.  The pressure pegs are assembled at an angle to impart direct bilateral compression to draw the matted surfaces together.  For an illustrated discussion of half-lap pressure peg points, see ibid, p. 34, figs. 11-a-11d, p. 41.

A set of four chairs with similar construction but with a gooseneck front post, is illustrated in Wang Shixiang, Masterpieces from the Museum of Classical Chinese Furniture, Chinese Art Foundation, Chicago, 1995, p. 60, no. 28.