SAN FRANCISCO  Apple has relied on slick applications, and even slicker advertisements, to promote the iPhone and maintain its advantage over rivals like Google in the battle to rule the next generation of smartphones.
But the fight may come down to something more provincial: who has the best lawyers.
On Tuesday, Apple sued HTC, the Taiwanese company that is the largest maker of smartphones running Google’s Android operating system, including the Nexus One, designed and sold by Google.
In the lawsuit, filed with the office of the United States International Trade Commission and the United States District Court in Delaware, Apple said that HTC phones running Android violated 20 of its patents, including those relating to the iPhone’s ability to recognize the touch of multiple fingers on its screen at once.
Since last fall, Google has been gradually adding multitouch capabilities to phones running Android through software updates.
Though the lawsuit singles out HTC, many patent lawyers and analysts say they believe Apple’s target is Google and the Android operating system, which the company gives away to cellphone manufacturers.
“We can sit by and watch competitors steal our patented inventions, or we can do something about it. We’ve decided to do something about it,” said Steven P. Jobs, Apple’s chief executive, in a statement. “We think competition is healthy, but competitors should create their own original technology, not steal ours.”
Apple and Google, once close allies, are now fighting for control of the market for smartphones, seen as the most important computing platform of the next decade. The battle has become emotional since last year, when HTC, Motorola and other phone makers began selling Android-based phones that offered a credible alternative to the iPhone.
In that time, the two companies have competed to acquire several start-ups, and Eric E. Schmidt, Google’s chief executive, left Apple’s board.
The lawsuit “is the opening shot in a war,” said Kevin Rivette, a patent lawyer and former vice president for intellectual property strategy at I.B.M. “Apple is island-hopping, attacking first the Asian companies. Then it can go after Motorola, gradually whittling away at Google’s base. They want to break the Android tsunami.”
In a statement, HTC said that it “values patent rights and their enforcement but is also committed to defending its own technology innovations.” The company said it had not yet had an opportunity to review Apple’s claims.
HTC said Wednesday in Taipai that it did not believe the lawsuit posed a short-term material impact to its business or that it would affect its forecast for the first quarter of this year.
Google said in a statement: “We are not a party to this lawsuit. However, we stand behind our Android operating system and the partners who have helped us to develop it.”
The iPhone, introduced in 2007, was the first cellphone that largely did away with physical controls, turning the entire device into a finger-activated screen. Apple had to invent new visual cues and software tricks so users could operate such a device, and the result was a product that wowed customers and seemed unique in the marketplace.
Now the iPhone looks less special. Other companies have sought to duplicate the technology, and similar touch-screen phones are available from Samsung, the BlackBerry maker Research In Motion and Google’s various partners, including HTC.
In the high-tech world, with start-ups and individual inventors claiming innovations, patents can be easily invalidated by courts, and many companies have tried to avoid expensive and time-consuming legal battles.
The wireless communications business has defied that trend somewhat. Broadcom and Qualcomm, two mobile component makers, sued each other for years over rights to wireless technology before settling last year. In October, Nokia sued Apple, claiming the iPhone infringed on 10 of its patents, and Apple countersued.
Now Apple, with its patent portfolio relating to multitouch controls and other ways these complex phones operate, apparently believes it has the legal leverage to slow down Google and the spread of Android.
Aside from multitouch, Apple says HTC also violated patents relating to how iPhone users can wake up their phones by swiping a finger over the image of a lock, and how users scroll through a list or document by dragging a finger down the screen.
As with all patent cases, a decision or settlement could hinge on whether lawyers for HTC  and perhaps Google, if they decide to help  can find “prior art” that demonstrates Apple’s innovations were not all that novel.
Such a task may not be that difficult. Palm sold touch-based mobile phones for years before the introduction of the iPhone, and is believed to have a large portfolio of patents. Synaptics, based in Santa Clara, Calif., is also a major owner of intellectual property related to touch screens.
These companies, and others, may now become valuable acquisition targets as the big players look to improve their position in the coming legal battles and the inevitable countersuits.
“Companies have been working on this for some time,” said Mark A. Lemley, a law professor at Stanford who also represents Google in some unrelated matters. “Now, it’s fair to say the Apple technology works better than prior generations of technology, so there may well be inventions there.”
Greg Aharonian, who runs the Internet Patent News Service, a site devoted to intellectual property news, said he believed that at least some of Apple’s patents would be found to be invalid. But he said the company’s goal might be to buy itself some time in the marketplace.
HTC Heroes Apple sued HTC, a Taiwanese manufacturer of mobile phones, on Tuesday, in a lawsuit claiming 20 different patent infringements, largely relating to the user interface of the iPhone, which is manufactured by Apple.

According to the lawsuit, filed with both the United States District Court in Delaware and the  United States International Trade Commission, HTC violated Apple patents pertaining to both multi-touch gestures, which allow users to interact with a device's touchscreen using multiple fingers, as well as patents involving more general touch features.  Devices mentioned in the suit are all phones manufactured by HTC that use Google's Android software.  The lawsuit says that HTC, in selling the phones, knowingly induced those using the mentioned products to violate patents owned by Apple, some of which were filed in the mid-1990s.

Although the lawsuit named only HTC as a defendant, many viewed the action as an indirect challenge to Google, as the lawsuit only covered HTC devices running Google's Android software.  The operating system has seen increasing popularity in the last year, and has increasingly included multi-touch input of the type mentioned in the lawsuit.  

One analyst, from Kaufman Brothers, said, "I think this is kind of an indirect lawsuit against Google."  Others said that Apple was suing HTC instead of Google because the phone manufacturer was an easier target than Google. Another analyst from MKM Partners said that "HTC is an optimal target for Apple-it's a relatively small vendor with a weak brand."

In the documents, Apple said that their goal was to permanently block HTC from importing and selling devices that had the offending qualities, as well a significant cash payment in damages.