Sony introduced what they called "Loop Surface" design language. The glass front curves slightly at the edges to meet the metal frame, and the back is crafted from a sturdy, matte plastic (polycarbonate) rather than glass. This was a controversial move at the time; critics argued it felt less "premium" than the glass-backed Galaxy S7 or iPhone 6s.
Launched in mid-2016, this handset represents a pivotal moment for Sony Mobile. It was the device that effectively retired the beloved Xperia Z series, ushering in the new "X" branding. While global variants of the Xperia X Performance were met with mixed reviews due to pricing and specifications, the Docomo Japan version (SO-04H) remains a fascinating case study in carrier customization, build quality, and the unique demands of the Japanese smartphone market. Official Sony Xperia X Performance SO-04H -Docomo Japan
This article explores the legacy, specifications, design, and enduring appeal of the SO-04H. To understand the significance of the SO-04H, one must understand the landscape of 2016. Sony had spent years refining the Xperia Z line, characterized by Omnibalance design and glass backs. Suddenly, at Mobile World Congress 2016, Sony announced the Xperia X series, promising a "new era" focused on intelligence and design. Sony introduced what they called "Loop Surface" design
However, owners of the SO-04H often praise the practicality of this build. The matte plastic is incredibly resistant to fingerprints and micro-cracks—a common issue with Sony’s previous glass phones. The ergonomic rounded edges make the device comfortable to hold, and it feels dense and well-assembled, weighing in at 164.4 grams. Launched in mid-2016, this handset represents a pivotal
The phone measures 143.7 x 70.4 x 8.7 mm. It fits perfectly in the hand, adhering to Sony’s philosophy of creating devices usable with one hand—something larger modern flagships
The Xperia X Performance was the flagship of this new line. In the Japanese market, Sony held (and still holds) a significant market share, largely due to its partnership with NTT Docomo. The SO-04H was the specific model number assigned to this flagship for Docomo’s network. Unlike the global unlocked models sold in Europe or the US, the SO-04H was tailored specifically for the Japanese carrier environment, complete with specific radio bands, e-money integration, and customized software. Visually, the Xperia X Performance SO-04H is distinct from its predecessors. While it retained the rectangular slab silhouette Sony is famous for, it moved away from the flat, glass-backed design of the Xperia Z5.
In the fast-paced world of smartphone technology, devices often fade into obscurity within months of their release. However, for enthusiasts, collectors, and fans of Japanese mobile engineering, certain models stand as monuments to a specific design philosophy. The —exclusively released for NTT Docomo in Japan—is one such device.
