A Reckoning for Kings by Chris Bunch and Allan Cole (Atheneum: $17.95; 384 pp.) Beach House 7by Paul Roadarmel (St. Martin’s: $17.95; 320 pp.)

The Vietnam War is a benchmark of American history if there ever was one. Before the fall of Saigon in April, 1975--positively and absolutely the end of U.S. involvement in Southeast Asia--you were hard pressed to find more than a handful of novels on the subject. Now, 12 years later, there are well over 200 novels, and no doubt as many histories, biographies, fictional memoirs, as well as stage plays, volumes of poetry, documentary and dramatic films.

“A Reckoning for Kings,” a novel by Chris Bunch and Allan Cole, is about the Tet Offensive of 1968, a military victory for the United States and its South Vietnamese allies, but an extraordinary political defeat. The title is taken from “Henry V,” one of Shakespeare’s great sword-rattling historical plays. The offensive raised questions about a bankrupt and overbearing foreign policy, the Johnson Administration’s credibility, and the workaday spirit of atrocity of the American armed forces. The novel, an excellent piece of work by two journeymen writers, makes one think.

Their story switches back and forth between the Vietnamese and the Americans, ranging across a vast scene that begins with the whole of Southeast Asia and ends with bitter street fighting in the fictional city of Song Nhanh. Gen. Duan (earthy and genuine, ambitious to liberate his country) moves the crack 302nd NVA Division south from Hanoi to join the general offensive in the Province of Song Nhanh. Hard-working and professional Maj. Shannon, on a recon patrol along the Ho Chi Minh Trail, sees Duan and his suite of staff officers and political cadre cross the Cham River on the Cambodian border. It can only be the headquarters staff of an NVA division--7,000 strong.

The reckoning is set in motion when Shannon tries to report to his new division commander, the hard-charging old tanker, Gen. Sinclair. The general is in Vietnam to punch his ticket and make some rank. The conventional wisdom from Saigon says there can’t be an NVA division poised in the Song Nhanh Province, so Sinclair does not believe Shannon’s report. Gen. Duan, a veteran of Dien Bien Phu, and his march-weary troops move to a prepared tunnel complex dug into a mountain called the Octopus.

Despite some telltale skirmishes, the division manages to remain undetected, and lies in wait for the general uprising scheduled to begin with the celebration of Tet, the Vietnamese New Year.

As the story moves back and forth among the many scenes of the Vietnamese and Americans coming inexorably closer to the landmark day, Jan. 30, 1968, the story also moves in and out. The large overall scenes cover the whole of the war in historical summary, neatly accomplished with the biographical asides of the main characters. The broad summaries lay the ground work for the close-in fire fight scenes of single well-aimed shots with M-16s and RPGs or discreet bursts with an M-60 machine gun or the solid volley of Chicom mortars. Young Sgt. Mosby and his squad (reluctant but fiercely competent) slug their way through many a fire fight, but not many of them drop by the wayside. All the characters meet in the capital city of Song Nhanh and fight street by street and doorway by doorway, eyeing each other over sandbag revetments and windowsill embrasures.

Bunch and Cole often talk in code--”Ossifer’s Club” for Officer’s Club. And they have a habit of using unfamiliar words: cut a chogie , the GI pronunciation of a Korean word that is the same as didi mau , which is Vietnamese for get out of here , scram! Bunch and Cole’s combined knowledge of the war in Southeast Asia is encyclopedic--how to rig your pack, what a starlight scope is, what is the sound of a company-size air assault, what it is to wallow in the squalor of the aftermath of a fire fight, on and on.

Overall, what the story gives you is a sense of the inevitable chaos of a military campaign; the incredible personal, physical pain; the extreme ugliness of the death that awaits even the most savvy line animal-- as grunts are called here. There is an elegant epilogue in which we learn the fate of the survivors--what happened to the survivors after the war.

“Beach House 7,” a novel by Paul Roadarmel, is a post-Vietnam War spy thriller that takes place in Bangkok--that most exquisite and beautiful of cities.

But the story begins during the last days of the war. The North Vietnamese are pouring into the South. Terrified refugees are fleeing south. The war will soon be over, once and for all. Lt. Peter Voss, one of the corporate army’s brilliant new systems engineers, and his ARVN assistant, Trang Van Thep, are driving north in an Army truck and bucking the hordes of refugees. They are trying to get to the Army’s computer complex at Cam Rahn Bay, code-named Beach House 7, where Voss’ machines monitor the broad array of MACV’s “Electronic Battlefield.” Voss must retrieve the MAS unit, a gadget he invented and attached to the MACV computers and has used to steal millions, but the crush of Vietnamese is too much, and he cannot get to it.

The story skips forward to 1977. Voss is in Bangkok where he lives with Kiri, a naive but well-endowed bar girl--if there is such a thing. He is still scheming to obtain his program from Beach House 7, retrieve his fortune, and put his considerable electronic skills to work on the network of electronic banking in the Far East. Voss runs a company on the river docks with the superbly benign title of Thai/Tech where he’s trying to duplicate the Beach House computers. He has just about everything but the MAS unit--the one crucial part that will make his scheme work. The moneybags of the company is a Thai prince who thinks the computers will be used for charting fishing fleets. Voss fully intends to cheat him blind, as he intends to cheat everyone.

He is joined by his old buddy Sloane, a pilot and part-time Air America spook just recently resigned from the board of directors of a large Hong Kong corporation. Sloane is privy to banking code numbers. Alice, a good-looking and dedicated do-gooder who worked for the People Project resettling refugees in Thailand, is also in the scene. She is everyone’s romantic interest. And hanging around is Jake Berman, a philosopher barfly and ex-UPI stringer who long ago concluded that the war was lunatic and nobody would pay him to write about lunacy. He somehow acts as conscience to the scheme.

And then the Korean, Mr. Park Sung Dai, comes on the scene--a bland and sinister white-collar warlord who was Voss’ partner in his Beach House 7 caper. Voss cheats him too, along with the Russians who come calling expecting to deal, and the Vietnamese who, strangely, don’t understand the computers at the beach house at all and don’t dare turn them off.

Roadarmel’s story is about the sprawl of corruption, routine graft, and baldfaced double dealing that were the broad underbelly of the war in Vietnam. Voss is eager to fight the war sitting behind a desk, and, like many a “patriotic” opportunist, saw the war as an easy way to make a fortune. And he did!

“A Reckoning for Kings” is a fine, well-crafted story about one kind of green machine--as the grunts called the Army and the Marines. “Beach House 7” is about the vicious greed of that other, ironical green machine, which has cranked out fortunes for the likes of Colt Firearms and General Dynamics, Hughes Aircraft and McDonnell Douglas, Honeywell and General Electric and a hundred others.