JAPAN CORPORATE PROFITS IN LAST 1986 QUARTER UP Current profits of Japan's major firms in the October-December quarter rose four pct from a year earlier to 5,654 billion yen against a 2.6 pct year-on-year rise in the preceding quarter, the Finance Ministry said. The improved earnings resulted mainly from a 22.5 pct profit increase in non-manufacturing industries, supported by an 88.7 pct rise for construction firms and a 138 pct gain in real estate, according to a ministry survey. Total sales of the 15,308 firms with capital of 10 mln yen or more which responded to the poll, fell one pct to 217,217 billion yen against a 1.2 pct fall the previous quarter. Current profits of manufacturing industries in the fourth quarter dropped 13.7 pct to 2,394 billion yen against a 22.1 pct fall in the preceding quarter, the ministry said. Plant and equipment investments of all firms polled fell 3.9 pct to 8,004 billion yen, compared with a 1.4 percent fall the previoius quarter. Ministry officials said the survey showed that the Japanese economy is in a delicate stage in which it is hard to tell if economic growth has stopped deteriorating or if the economy is heading for a recovery.