diff --git a/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipInferenceService.java b/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipInferenceService.java
index 96d7fa50..3226f1b6 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipInferenceService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipInferenceService.java
@@ -97,8 +97,8 @@ public class RelationshipInferenceService {
             List<RelationToken> path = shortestPaths.get(id);
             PersonNodeDTO node = new PersonNodeDTO(
                     p.getId(), p.getDisplayName(),
-                    p.getBirthDate() != null ? p.getBirthDate().getYear() : null,
-                    p.getDeathDate() != null ? p.getDeathDate().getYear() : null,
+                    RelationshipService.yearOf(p.getBirthDate()),
+                    RelationshipService.yearOf(p.getDeathDate()),
                     p.getGeneration(), p.isFamilyMember());
             out.add(new InferredRelationshipWithPersonDTO(node, labelFor(path), path.size()));
         }
diff --git a/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipService.java b/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipService.java
index e764da04..51b312c6 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipService.java
@@ -158,8 +158,9 @@ public class RelationshipService {
     }
 
     // Stammbaum DTOs stay year-shaped: derive the year from the LocalDate, null-safe
-    // for persons with no date entered (ADR-039, REQ-PERSON-DATE-01).
-    private static Integer yearOf(LocalDate date) {
+    // for persons with no date entered (ADR-039, REQ-PERSON-DATE-01). Package-private
+    // so RelationshipInferenceService shares the same derivation.
+    static Integer yearOf(LocalDate date) {
         return date != null ? date.getYear() : null;
     }