World Chess Championship 1886 (Wikipedia)

This source backs 18 claims across the atlas. As facts: 14 well-attested. As cited relationships: 1 holds, 1 connected. Plus 2 entities citing it as a general reference with no single fact or relationship attached.

Disposition By Topic

• Open Questions, 8 claims: 6 well-attested, 1 connected, 1 general references.
• Milestones, 7 claims: 5 well-attested, 1 holds, 1 general references.
• Sources, 3 claims: 3 well-attested.