I just received an email from a good friend in Japan, who has notably over the past few months been instrumental in connecting me to various people, for some research interviews I've been conducting.
The data collection phase of the research has long been completed, but she has just sent me an email with some additional data attached. Given we haven't communicated for some time (as I've been writing up the results of the research, and the phase of research she was helping with is over), her email starts thus:
ヘンリー
ご無沙汰しています。
I'm aware of the meaning of the phrase 「ご無沙汰しています」 -- but how best to respond to it in my reply?
Would a simple 「こちらこそ」 suffice, or would maybe 「私もご無沙汰しています」be better?
I had also considered 「ご無沙汰していますね」 but I don't know if that's got a potentially rude connotation here (i.e. I'm somehow highlighting the lack of communication on her side, rather than agreeing to the plain fact that we've not communicated for a while).
Many thanks! よろしくお願いします。