They're both gymnosperms, plants bearing "naked seeds," i.e. their unfertilized seeds are unenclosed, open to the air for direct fertilization by pollination.
Additionally, they are both fairly ancient species — cycads have been around since at least the early Permian, roughly 280 million years ago (though most extant cycad species have evolved in only the last 12 million years) — and the gingkos nearly as long, 270 million years.
And, you can find both species here on Shikoku.
*Illustration above from Dokobara by Kumiko Takeuchi 2008