A couple of years ago we flew FRA-HND-PEK (23hours transit) - ICN. Our plan was to visit the city relying on getting entry with TWOV (EU passports). Upon arriving at PEK, the visa officer initially refused entry because our stay was less than 24h, and he insisted we spend the night at the airport transit area. Luckily, our luggage was only tagged to PEK so after a lengthy consultation with Air China representatives, the grumpy visa guy finally gave us the required stamp to allow access to immigration and entry.