Aloysius Low/CNET

If there is one thing Sony has learned in watching the rise of Samsung over the past decade, it's been the singular power that smartphone leadership affords.

In recognition of this, Sony acquired Ericsson's stake from its 10-year joint venture last year and created Sony Mobile. The evolution of the Sony-Ericsson mobile product line had reflected Sony's fortunes. Imbued with such winning subbrands as Walkman and CyberShot in the feature phone era, it had to start from scratch with a new brand -- Xperia -- in the converged smartphone era. And despite phones that have won praise for their appearance, it had been slow going for those phones. Samsung sits atop an Android market share mountain that Sony seeks to climb, seeing HTC and Google-owned Motorola above it.

Now, though, Sony Mobile is working on the next big thing in mobile ... and the next small one. Perhaps taking a swipe at Samsung, which has become notorious for launching bigger and bigger phones, Sony has introduced the Xperia Z Ultra, a 6.4-inch grip-defying behemoth. The Ultra stands to take the smartphone size crown away from even the forthcoming 6.3-inch Samsung Galaxy Mega, which in turn had pushed past the boundaries of Samsung's Galaxy Note that popularized phones above 5 inches.

Sony Mobile also recently introduced its SmartWatch 2, the fourth generation of its smartphone-connected Bluetooth timepieces that began with a small text display overlaid on an analog watch face. While rumors swirl that Apple, Google, Microsoft, and Samsung will all launch smartwatches, Sony is for now the only major company making a full-screen smartwatch, what with the MotoActv having faded from view in light of Google's quiet Motorola makeover.

In fact, the smartwatch is well-timed to the introduction of the Xperia Z Ultra. The larger a phone is, the less convenient it may be to have it nearby, and the more value the glanceable user interface of a smartwatch may have.

These kinds of devices -- the first and the only -- harken back to the kinds of products that consumers once considered synonymous with Sony. The storied electronics maker has not completely lost its knack for creating such gadgets. This is evidenced in its digital imaging group, which has stuffed APS and full-size camera sensors into compact form factors. However, smartphones in the sweet spot of the market, like the Galaxy S4 and iPhone, won't see the shadow of the imposing Ultra.

And so far, despite an affordable and broadly compatible product, Sony's tenacity in smartwatches hasn't resulted in it spawning a mainstream smartwatch market. Indeed, Apple has been the only company to really single-handedly drive new categories in the past 15 years with the iPod (a particularly sore point for Sony and the Walkman) and iPad.

When Sony was raking in high margins on televisions and other audiovisual equipment, it could afford to experiment in niche devices that captured the imagination at high price points such as the Aibo robotic dog, the Google Glass of its day. The innovations in the new Sony Mobile product line are a good sign that the company is making progress in mobile, but they will only be true successes if their halos can translate into more success in higher-volume products down the road.