What with Android, iOS, Blackberry and Windows Phone all fighting tooth and nail for a piece of the mobile operating system pie, you’d have to be mad to think there was room for a fifth, all-powerful contender, wouldn’t you?

Apparently not, or at least not if your name happens to be Samsung or NTT Docomo, or any one of half a dozen telecommunications giants throwing their weight behind a new OS called Tizen.

Just like Android, Tizen is derived from Linux and its development is being pushed chiefly by Samsung, Intel and the Linux Foundation as a genuine, open-source alternative to those operating systems mentioned above. It’s actually been around since January 1^st of last year, although its initial release largely went under the radar at the time as very few devices have adopted it.

That’s all likely to change in the next few months though, with reports from Japan suggesting that Samsung has teamed up with NTT Docomo to release the first ever smartphone running the Tizen OS to Japanese customers sometime in 2013.

The report, published by Yomiuri, suggests that both Samsung and Docomo’s share concerns over the dominance of Android and iOS, which currently control about 90% of the mobile market. Apparently, it’s not just Asian companies that are worried about this US dominance either – European carriers such as France Telecom and the UK’s Vodafone have both shown a lot of interest in the Tizen project.

Tizen’s community proclaims that their OS is the first ‘true’ open source operating system, unlike Apple’s iOS and even Android. Google’s OS, which is generally thought of as being open source, is in fact only partially open – the underlying platform cannot be significantly changed, and so carriers cannot offer their own services with it.

On the other hand, Tizen is 100% open source, which means that the blueprints of the underlying technology will be made available to all so carriers and service providers can modify things to offer their own services. For example, Docomo would be able to offer its online shopping services on any phone built on Tizen. Another advantage of Tizen is that it isn’t restricted to just smartphones and tablets. As well as these devices, it can also be run on Smart TVs, PCs, notebooks, GPS devices and in-car infotainment systems.

For NTT Docomo, the prospect of being a major partner in the alternative OS is particularly tempting, considering that it’s the only major telecommunications firm in Japan that doesn’t sell the iPhone. This has become a major problem for Japan’s biggest carrier, which has seen its new subscribers fall to a five year low as a result – obviously, it will be pinning its hopes on Tizen being able to win back all of those customers it has lost.

Meanwhile it would seem that Samsung is interested in regaining control of its mobile OS environment, despite generally being viewed as Google’s “partner” when it comes to Android. While it would be a shock is Samsung threw its full weight behind Tizen now, the Korean firm has never been 100% committed to Android, having previously used its own OS “Bada”, and more recently, developed products running Windows 8.

What with Google rumored to be bringing out a flagship Motorola phone later this year, it’s pretty clear than neither they nor Samsung have much trust in each other, hence both companies look to be hedging their bets. For now, Samsung will likely stick with Android for its newest, high-end phones (like the Galaxy SIII), but if Tizen takes off as a genuine alternative that may not always be the case…