The invention of the Han dynasty that was called the "wooden ox" is the wheelbarrow. To find this answer, you can start by doing a search using keywords such as "inventions of the Han dynasty." This will provide you with a list of inventions associated with that time period. From there, you can look for information specifically on the "wooden ox" to confirm that it indeed refers to the wheelbarrow.
The invention of the Han called the "wooden ox" is the wheelbarrow.
