(FORTUNE Magazine) – Is T. Boone Pickens trying to greenmail the richest company in the world? Notably inactive in the U.S. lately, the corporate raider chose an unlikely overseas target when he secretly bought 20% of an automobile parts manufacturer affiliated with Toyota Motor Co. The No. 1 Japanese automaker owns 19% of Koito Manufacturing and isn't likely to hand over those shares to Pickens or fork over part of its $13.5 billion cash hoard to buy Pickens's holdings at a higher price. In Japan, where companies are barred from buying their own stock, the standard greenmail scenario requires an ally to do the purchasing. Pickens has said he is interested in Koito solely as an investment in a growing company, but some Japanese bankers are interpreting the Texas-based Boone Co.'s move as a battle cry. While Japanese companies have been snapping up U.S. enterprises, almost no action takes place in the opposite direction. One reason: Big chunks of Japanese corporations are held by friendly firms with no intention of trading. Some Japanese see a fiendish American plot. ''The Americans want to make this a political issue,'' says an M&A executive at one of Japan's leading securities firms. Officials at Boone Co. aren't unmindful of the policy implications. Says Sidney Tassin, the VP of finance: ''I think the transaction will sharpen the focus on the lack of reciprocity in Japan.'' ''Acquisition'' is still a dirty word in Japan, where companies euphemistically call their mergers and acquisitions sections ''corporate development services.'' While they have dabbled in M&A overseas, Japanese companies still shy away from testing their skills on domestic turf. According to a survey by Yamaichi Securities, Japanese companies were involved in 117 mergers or acquisitions in the first quarter of 1989. Eighty of those deals involved foreign companies, all but two overseas. Reticence aside, the 117 cases added up to $3.6 billion -- almost four times the value of all Japanese M&A transactions in 1985.