BANK OF JAPAN BUYS DOLLARS IN TOKYO, DEALERS SAY The Bank of Japan bought a modest amount of dollars at around 145.10 yen just after the market here opened, dealers said. Just before the opening, the dollar dropped swiftly as speculators concluded the Group of Seven (G-7) comminuique issued in Washington contained nothing basically new, they said. It fell about a half yen, to around 145. The G-7 reaffirmed that their currencies around current levels reflect economic fundamentals. One dealer said the Bank of Japan probably intervened in Australia before the opening here, but could not confirm this.