My Tenso package arrived today.
If a Japanese merchant fails to include the value of your package, Tenso cannot complete the necessary information for your Express Mail Service (EMS) package or the U.S. Customs form. Tenso also needs this information if you request insurance. Tenso will alert you with a pop-up to enter the package’s value.
Click the package number and enter the package’s value. This might be difficult if you have more than one package missing values. In that case, check the merchant’s name, tracking number or date shipped.
I just found out. Tenso had sent me a EMS tracking number along with a link to the JP Post to track it. Well, following your package through JP Post dead ends once it leaves Japan. USPS can track your package too using the same tracking number. USPS can even track your package in Japan. Just enter your EMS tracking number on USPS’s Track & Confirm page.