Authenticating unsigned or unmarked porcelain sculptures can be challenging but is achievable through a combination of expert evaluation, scientific testing, and historical research. Here are the most effective methods:

1. Expert Visual Inspection: Skilled appraisers examine the sculpture’s style, glaze, and craftsmanship to identify the era or origin. Details like brushstrokes, color palette, and decorative motifs can reveal clues.

2. Material Analysis: Techniques like X-ray fluorescence (XRF) or thermoluminescence (TL) testing determine the composition and age of the clay and glaze, helping verify authenticity.

3. Provenance Research: Tracing the sculpture’s ownership history or comparing it to documented works from known artists or periods can provide critical evidence.

4. Comparative Study: Matching the piece to similar signed or marked works in museums or private collections can help identify its maker or era.

5. Consulting Specialists: Engaging ceramic historians or auction house experts ensures a reliable assessment, especially for rare or high-value pieces.

By combining these approaches, collectors can confidently authenticate unsigned porcelain sculptures and uncover their true value.