What is the first electronic watch -- the pioneer on the road to the perfect (thinnest: Concord Delirium; most precise: Omega MegaQuartz or The Citizen) quartz watch?

Is it the LIP reference 607, (electric / electronic) caliber R27 presented in 1958 because of the diode used to prevent sparking?

Or is it the Bulova Accutron caliber 214 tuning fork presented in 1961?

Well, to our understanding the title "First Electronic Wristwatch" goes to the Bulova Accutron because electronics make the whole concept work, while the LIP uses the diode (electronics) just to prevent sparking in an overall electric movement -- the watch would work without this electronic module, although worse and less reliable. Anyway, the LIP is definitely an interesting and innovative watch with an outstanding and reliable electric movement, that has its merits over the more popular Hamilton cal500. And not to mention the watch case of the LIP: the size of the movement, that was necessary because of the two batteries inside, is hidden behind the lugs, making the visible watch normal sized and a very stylish and modern appearance, of much higher quality than the Hamilton Electric.

ADDENDUM: Make sure to have a look at the watch strap in the photo of the vintage print advert -- the lower part looks seriously used, just to underline practicability of the LIP. ;-)