The point of Chess is to have *different* moving pieces in minimal rules with maximal challenge. We pair pieces except royal King. He is one step all directions, and his companion is appendage of that method. An appendage may be little or may be big. Originally, the little Adviser, next to King in the middle, was one-step diagonal, a half-King. That was Chaturanga and Shatranj. Then they made this companion to King, big Queen, a super-King going as far as she wants, no longer half-king, but double, triple...up to sevenfold, times 7 the King in all 8 directions. The modern Queen of final 20th century establishment by f.i.d.e., in recognition of her over 400-year existence. In Chaturanga and Shatranj, as far as the paired supporting cast, crucial to play, Knight and Rook always set off nicely, being mutually exclusive. But Bishop, their Bishop counterpart over extended centuries 600-1500, across India to distant Spain or Portugal, was weaker than the Knight. She had only a two-step diagonal leap, and so all the squares do not get filled in. Around 1500, revolutionarily, her move was extended to all-diagonal, 1, 2, 3 and onward without the leap, the latter lack of leap a modest reverse-damping. She becomes in named Bishop, Runner, Fool as we know the ecclesiastical piece today. Now during the current years 1500-2000+ we still live in, paired Bishop is the half- (or quarter singly) Queen to Queen's being 7 or 8 times King -- depending whether thinking of reach or of direction -- the way similarly that earlier adviser out of India, Persia, Arabia was a counterpart-adjacent half-King. The paired complementarity of Rook-Knight-Bishop is perfected, all of R,N,B going to their mutually exclusive squares from any departure square, 5x5 surrounding. No overlap at all like if and when avant garde designers stick in, for example, a Chinese Cannon, who considerably duplicates Rook's way of moving. The result of having both Rook and Cannon together is always the uglification of Xiangqi itself [Make no mistake: Because of balancing rules by split board, palace etc., Xiangqi is excellent regional chess variation, sometimes dominant, but its definitional piece-types are inharmonious in themselves.] Moreover then, R+N+B have modes differing among themselves in that one leaps naturally, and that each Bishop is colourbound unlike Rook. This is the core Chess, (K,Q)+(R,N,B) going forward. Once again, like in the Bishop revolution year 1500, with the necessary wider view of 7x7 squares surrounding, not just 5x5, there is a fourth complement. Namely, also paired Falcon, discovered by degrees over the years 1988-1992, as the fourth piece-type (or the first piece--whichever way looked at) maintains R-N-B-F, both in, first, all fulfilling the mutual-exclusivity desideratum and, second, in all having those different modalities. The two aspects are the critical challenge. There are now one leaper, one multi-path fixed-length of greater power than that leaper, one slider, and one half-the-board-reach slider in Knight-Falcon-Rook-Bishop, each respectively so characterized. This comment's first sentence says ''challenge,'' and the word is repeated two sentences back; it has yet to be proved that Computers have to present a problem to one fundamental goal to level the playing field between man and machine, when all four natural complementary piece-types, R+N+B+F, get used, as is correct, once the full internexus is, and has been, discovered. //// Chess Morality Poems I to XX are published, and continuation in XXI to XXX will turn to ecology and environment in respect for and on behalf of 4th worlders, who are indiginists, native peoples worldwide, to idealize salvaging, saving up to half the threatened biological world, if we're lucky, being devastated as we speak by the philosophy of conquest for 500 years and by human overpopulation, and heinously implemented worldwide since especially 1970. Poem XX, the next one, which can be read linkwise here, now not referring to this XIX, which ''Shadow Chess'' was chosen for being uncommented the four years, left off lamenting artificial climate change, to the extent unaddressed sure to change drastically our ways of life, if they continue recognizably at all.