Yes, Japanese children under the age of 12 may qualify for the JR Pass even if they have not lived abroad for a full 10 years, provided they meet specific "family living arrangement" criteria defined by the JR Group.

The "Household Member" Exception:

For a child (under 12 on the day of voucher issuance) to be eligible, the following conditions must be met:

• Living with a Qualified Adult: The child must reside at the same address as a Japanese national who has already met the "10 consecutive years of residency" requirement.
• Combined Documentation: The child's name must be listed on the same "Copy of Overseas Residential Registration" (Zairyutodoke no Utsushi) as the qualified adult. The registration date for the adult must be at least 10 years old.
• Traveling Together: The child must exchange the voucher and travel within Japan together with the adult who meets the eligibility requirements.

Important Limitations:

• If a child under 12 is listed on a separate residency document from the qualified adult, or if the adult they live with does not meet the 10-year rule, the child will not be eligible.
• If the "Date of Arrival" for the child is blank on the document, JTB/JR may verbally verify the duration, but consistency with the adult's record is required.