The Linear B sign a2 (also known as sign *25) was closely examined and discussed in the years immediately following the decipherment. It was determined that a2 represents ha. While scholars noted that the sign a2 was rare in Crete, but frequently found on the mainland, they did not explain this unequal distribution. In this contribution in honor of José L. Melena, who has done so much to help us understand how the Linear B syllabary originated, developed, and was used, I reexamine the use of sign *25 through time and space in the Mycenaean palatial period. I take into account the new corpus of Theban tablets (with many attestations of a2), the new Ayios Vasileios tablets, and the new chronologies of the Knossos archives. I observe that sign a2 is used in the Room of the Chariot Tablets (RCT) and North Entrance Passage (NEP), but not in the later phases of the Knossos archives, whereas a2 occurs regularly in words on Linear B documents from the mainland sites of LH IIIB Pylos, Thebes, and Mycenae, and also at Ayios Vasileios. I suggest that sign a2 is an isograph, a distinguishing feature of the early phase of the Knossos administration, which was abandoned in the late Knossos phase. This isograph continued in use in the scribal traditions of the mainland palaces.