Software specifically created for the Nintendo DSi will be region-locked, meaning that European software will only work on European consoles, and more importantly US and Japanese software won't.
Previous DS handhelds - and GameBoys before them - had been region-free, meaning that software purchased in the US or Japan could be played on European hardware.
However, Nintendo told Eurogamer this afternoon that DSi is region-locked "because DSi embeds net communication functionality within itself and we are intending to provide net services specifically tailored for each region".
"Also because we are including parental control functionality for Nintendo DSi and each region has its unique age limit made by different independent bodies."
The good news is that this only applies to software that is compatible exclusively with the DSi, and that existing DS software remains region-free. Internet browsing and photo sharing also works globally.
Also, Nintendo's statement specifically refers to "software" rather than "games". We've asked for clarification as to whether this is likely to affect a lot of game releases going forward, but, assuming the platform holder hopes to continue selling DS Lites in large numbers, we'd be surprised if it does.
Update:Nintendo has told us that software is their term for everything these days, including games products, so it sounds like the DSi's region-locking will be broad-based on all releases that require the new hardware.
The Nintendo DSi is due to launch in Japan on 1st November, and Nintendo UK has previously said that the revised hardware - sporting a bigger screen, a camera and an SD card slot - will launch in Europe next spring.