Sitecore Child Item Count Module is for getting the child item of the selected item in Content Editor. It also provide an option to specify the template id of child item, if you want to fetch the items of any specific template. It works based on the index. It also check the current Language. If your current selected language is Japanese and if the child item doesn’t exist with Japanese language version than it won’t include in child count.
For more information: Documentation
Download it from – Sitecore Marketplace
Source Code: GitHub