Multiple transits

We are planning to fly UK - Guanzhou - NZ straight through. We are travelling using NZ passports. However on the way back we are wanting to transit Tokyo, so NZ - Guangzhou - Tokyo (for 4 nights) - Guangzhou - UK. Do we need a china visa to allow this to happen, if there's a need to sleeping stop over in Guangzhou on either of these transitions?

Thank you, Wendy