The Nintendo Network is undergoing "emergency maintenance" from Jan. 28 to Jan. 29, resulting in temporarily unavailable services to areas of the system, Nintendo announced.
According to the company, this maintenance will affect Nintendo Network features including the online Wii U and 3DS eShops, the DSi Shop and Wii Shopping Channel. In addition, network services on both Pokemon Black and White 1 and 2 as well as ranking and matchmaking functions on Warriors Orochi 3 Hyper for Wii U will be affected.
"During the emergency maintenance, parts of the affected services may be intermittently unavailable," said Nintendo in a statement on the website. A full maintenance schedule is available here.
We have contacted Nintendo for details on what the nature of this "emergency" entails and will update when further information is available.