Zen International Patents and Trademarks

Casio G-SHOCK, which was released from Casio Computer Co., Ltd. in 1983, is now experiencing a resurgence in popularity.

G-SHOCK shipments in fiscal 2016 was 8.5 million units and reached record high.

Well-known brands like “G-SHOCK” are often targeted for imitation.
In the past, a huge number of “G-SHOCK” counterfeit products including those with the mark such as “A-SHOCK” etc.  appeared in the markets.

Casio owns 26 trademark registrations from “A-SHOCK” to “Z-SHOCK” as a countermeasure for imitation.

By the way, “G” of the G-SHOCK is the word derived from “gravity”.

Source: http://g-shock.jp/