According to the Embassy of Japan in Canada,
A transit Visa is for travelers who are stopping over in Japan en route to another country due to flight schedules.
- Canadian citizens and nationals of countries with Reciprocal Visa Exemption Agreements with Japan do not require a Transit Visa. (List of the countries) As of March 16 2023, Canada is on the Reciprocal Visa Exemption Agreements list. India is not.
- No visa required for all nationalities if you are transiting through Japan within the same airport without leaving the secured area.
This information allows us to answer your question:
- If you do not need to leave the secured area of your arrival airport to take your connecting flight, you do not need a transit Visa.
- If you need to leave the secured area, you do no need a transit visa if the passport you use to travel is on the Reciprocal Visa Exemption Agreements list. If your nationality is not on the list, you need a transit visa.
Some reasons you could have to leave the secured area are:
- Change of airport for connecting flight.
- Change of airport terminal.
- Layover too long to stay in the secured area (not all airport terminals are 24h, or different airport zone).