Tokyo stocks closed the morning session up slightly on Monday, with the Nikkei Stock Average reaching its highest level in eight and a half months on hopes that the yen will remain weak. The benchmark index finished the morning at 10,148.22, up 18.39 points, or 0.18%. The gauge temporarily soared to 10,172, its highest point since July 8, 2011, when it reached 10,207. Before the opening bell, the euro briefly rose to the 110 yen level for the first time in four and a half months. The dollar moved slightly around the mid-83 yen level, but the decline of the yen provided a sense of relief among investors. However, the gauge later trimmed its gains after buying ran its course. Few investors appeared eager to take positions one day before a national holiday. The trading value on the first section of the Tokyo Stock Exchange reached 524.1 billion yen, with 998.96 million shares changing hands. On the first section, 990 issues rose, 503 declined and 165 remained unchanged .