The Japanese navy (JMSDF) has currently 4 Kongo, 2 Atago and 2 Maya class AEGIS destroyers.
2 additional ships are planed:
https://www.navalnews.com/naval-news/2023/01/japan-to-increase-the-number-of-aegis-destroyers/In addition, to ships specialised for defense against ballistic missiles equipped with SPY-7 and SM-6 will be built:
https://www.navalnews.com/naval-news/2022/12/japanese-mod-releases-further-details-of-asev-bmd-destroyers/P.S. In English articles, all these ships are called "destroyers" - but as we had learned in another topic about the ships for defense against ballistic missiles, the Japanese navy does not call them destroyers (but uses DD, DDG hull numbers). E.g. the Kongo class is called "護衛艦「こんごう」型" = "Escort vessel 'Kongo' type":
https://www.mod.go.jp/msdf/equipment/ships/ddg/kongou/