Pagasa Industrial v. Court of Appeals 204 Phil. 162
(1982)

“It appears that it was only after more than seven (7) years when respondent sought the cancellation of the trademark. An unreasonable length of time had already passed before respondent asserted its right to the trademark. There is a presumption of neglect already amounting to "abandonment" of a right after a party had remained silent for quite a long time during which petitioner Pagasa Industrial Corporation had been openly using the trademark in question. Such inaction on the part of respondent entitles petitioner to the equitable principle of laches (Section 9-A of the Trademark Law, as amended).”

[Dissent of J. Aquino which was upheld in Pagasa Industrial v. Court of Appeals, GR L-54158, Aug. 31, 1984]

“Pagasa Industrial Corporation cannot invoke the defense of estoppel by laches, an equitable doctrine, because it acted in bad faith in registering its trademark "YKK" in l967. He who comes into equity must come with clean hands. Pagasa acted in bad faith because it had prior knowledge that the trademark "YKK" had already been appropriated by Yoshida Kogyo Kabushiki Kaisha. That trademark "YKK" is in fact an acronym of Yoshida Kogyo Kabushiki Kaisha (YKKK), a multinational Japanese corporation, one of the biggest zipper manufacturers in the world.”