Nintendo has opened a mysterious Japanese website titled “2018.1.18” with the above image and the text “On January 18 (Thursday) at 7:00 a.m. [JST], “New Play” using Nintendo Switch will be introduced on this page.”
January 18 at 7:00 a.m. JST is January 17 at 2:00 p.m. PT / 5:00 p.m. ET / 10:00 p.m. UK, meaning whatever Nintendo plans to introduce will be unveiled later today.
Update 7:55 a.m.: The Nintendo UK version of this page has provided more information about what will be unveiled. It reads: “Tune in to discover a new interactive experience for Nintendo Switch that’s specially crafted for kids and those who are kids at heart.”