suffice to establish a complete and consistent ordering of all terminal nodes — if it cannot consistently order all of the terminal nodes in a tree, the tree is illicit. Consider the following tree: (S and S' may either be simplex structures like BP, or complex structures with specifiers and complements like CP.) In this tree, the set of pairs of nonterminal categories such that the first member of the pair asymmetrically c-commands the second member is: , , }. This gives rise to the total ordering: . As a result, there is no right adjunction, and hence in practice no rightward movement either. Furthermore, the underlying order must be specifier-head-complement. Derivation of X-bar theory The example tree in the first section of this article is in accordance with X-bar theory (with the exception that [Spec,CP] (i.e., the specifier of the CP phrase) is treated as an adjunct). It can be seen that removing any of the structures in the tree (e.g., deleting the C dominating the 'c' terminal, so that the complement of A is [CP c]) will destroy the asymmetric c-command relations necessary for linearly ordering the terminals of the tree. The universal order Kayne notes that his theory permits either a universal specifier-head-complement order or a universal complement-head-specifier order, depending on whether asymmetric c-command establishes precedence or subsequence (S-H-C results from precedence). He prefers S-H-C as the universal underlying order since the most widely attested order in linguistic typology is for specifiers to precede heads and complements (though the order of heads and complements themselves is relatively free). He further argues that a movement approach to deriving non-S-H-C orders is appropriate since it derives asymmetries in typology (such as the fact that "verb-second" languages such as German are not mirrored by any known "verb second-from-last" languages). Derived orders: the case of Japanese wh-questions Perhaps the biggest challenge for antisymmetry is to explain the wide variety of different surface orders across languages. Any deviation from Spec-Head-Comp order (which implies overall Subject-Verb-Object order, if objects are complements) must be explained by movement. Kayne argues that in some cases, the need for extra movements (previously unnecessary because different underlying orders were assumed for different languages) can explain some otherwise mysterious typological generalizations. His explanation for the lack of wh-movement in Japanese is the most striking example of this. From the mid-1980s onwards, the standard analysis of wh-movement involved the wh-phrase