Kohl's arms offer a real surprise. Call to negotiate limits on all nuclear weapons categories denotes Bonn's worries about its position as likely battlefield

West German Chancellor Helmut Kohl delighted the Soviet Union and confused his allies (including his own foreign minister) with his surprise call Friday to negotiate with the Soviets about limiting all nuclear weapons of every range in Western Europe. In Moscow, Soviet Foreign Ministry spokesman Gennady Gerasimov promptly welcomed the idea. The Soviet Union has long wanted to denuclearize Europe, since it enjoys conventional superiority in the European theater in combat forces and heavy ground weapons. Neutralization of nuclear weapons would enhance the importance of this superiority.

Allied spokesmen were noncommittal about Dr. Kohl's statement over the weekend while they sought to sort out what it meant.

Allied defense ministries were nonplussed, however, since the West has long depended on its nuclear weapons to offset the Soviet conventional superiority.

The West German Foreign Ministry, which was conspicuously not informed about Kohl's statement in advance, gave the minimal response that the statement did not mean that Bonn was setting new conditions on the Euromissile arms control deal shaping up between the superpowers.

The United States and Soviet Union are now discussing the elimination of intermediate-range nuclear forces (INF or Euromissiles) from Europe. The two subcategories of Euromissiles on the table in the Geneva arms talks are the longer-range INF and the shorter-range INF. The West German government has yet to make a formal announcement of where it stands on the issue of removing shorter-range Euromissiles, though it has said it is in favor of removing the longer-range Euromissiles.

For his part, West German Defense Minister Manfred W"orner, in a newspaper interview yesterday, chose to downplay any policy implications of Kohl's statement and to stress instead Kohl's general reference to the importance of eventually building down Soviet conventional superiority.

Kohl's declaration came within hours of the communiqu'e of NATO's Nuclear Planning Group in Stavanger, Norway, which left open NATO policy on shorter-range Euromissile arms control, largely because of indecision in Bonn about how to proceed. Given its own non-decision, the Nuclear Planning Group clearly did not press Kohl into declaring himself.

What apparently did spur him to a statement, after weeks of saying that Europe would not be pushed into a hasty choice, was the statement of the previous day by British Defense Secretary George Younger that London would support the Euromissile deal if other steps were taken to maintain nuclear deterrence in Europe.

Until then, Bonn had hoped that London would join it in rejecting the ``second zero option'' of doing away with all shorter-range INF (with ranges of between 500 and 1,000 kilometers, or 300 to 600 miles). The original ``zero option'' calls for removing all longer-range INF (between 1,000 and 5,500 km, or 600 to 3,400 miles) from Europe.

French Premier Jacques Chirac (though not French President Francois Mitterrand) did back Bonn's desire to reject the second zero option, but since France is neither a member of the NATO military command nor of the Nuclear Planning Group, London's decision left Bonn isolated within NATO.

Bonn's discomfort arises from its singular position as the nonnuclear frontline state that would be the prime battlefield in any European war.

From the German point of view today, removal of the 1,000-5,500-km range weapons - which the West first proposed at Bonn's prodding six years ago, and which Moscow suddenly accepted in February - starts at the wrong end of the spectrum, since it would leave Soviet territory as a sanctuary from European nuclear weapons, while preserving those shorter-range arsenals that in effect could be used only in Germany.

The further down the line cuts go, the more obvious this effect. Hence the West German unease with getting rid of the shorter-range Euromissiles as well as the 1,000-5,500-km range. As Kohl pointed out in his statement, elimination of all Euromissiles above 500-kilometers ``would ignore precisely those weapons which threaten our land above all others.''

Bonn's allies understand this special sensitivity and try to accommodate it. But at the moment they have difficulty understanding what means Bonn prefers for coping with the singular vulnerability conferred on it by geography.

From the point of view of Bonn's allies, once the Soviet Union revived the Western offer of zero Euromissiles, Bonn had two options. It could assume that nuclear deterrence of any Soviet conventional attack is really rather sturdy - whatever the West's specific nuclear weapons - and then go on to claim Euromissile arms control as a great success for West German policies.

Or else it could decide (as the British have now done) that the Euromissile deal could weaken nuclear prevention of war - and therefore insist on compensatory measures of modernizing the remaining nuclear weapons as the necessary condition for its acceptance.

Kohl, however, has never chosen either of these positions. His latest statement still straddles them.

On the one hand, he praises Euromissile arms control as a precedent-setting ``full elimination of an entire weapons category;'' pledges full support to President Reagan in arms control; and urges a Soviet-American summit ``to set the seal on the breakthrough in arms control.''

On the other hand, he says that ``innate German interest'' requires that negotiations not be confined to only part of the weapons spectrum, and should include missiles under 500 km, chemical weapons, and conventional forces.

Kohl cannot bring himself to say publicly what both his defense and foreign ministries are convinced of: that NATO fields nuclear weapons not to counter Soviet nuclear weapons - but rather to counter their superior conventional forces.

In public, Kohl implies that NATO fields nuclear weapons to counter those of the Soviet Union, and that a ``zero solution'' for all nuclear weapons is the goal. Yet precisely because this was the implication of his latest statement, Dr. W"orner felt obliged to specify in his interview that negotiating about nuclear weapons with ranges between zero and 500 km would not not necessarily lead to a zero solution in this category, but lead to agreed ceilings.