Palace Tablet C18: the Distance Number Introductory Glyph, 'u-tz'ak-ah / utz'akah. (Photo: Mark Van Stone)

Because it occurs in the Distance Number Introductory Glyph, J. Eric Thompson suggested that the top collocation on the right above (with the curved lines crossing a straight line) should be read as hel "change". Later, Berthold Riese suggested a reading of hel, hal or tz'ak. Nikolai Grube, citing his identification of the "nine successor" title as Bolon Tz'akab, has supported the tz'ak reading. (Freidel et al 1993: p. 416, n. 11.)