Nikkei drops on caution over Greece, up for the week
TOKYO, June 26 (Reuters) - The Nikkei share average slipped on Friday as investors opted for caution while waiting to see whether Greece can clinch a deal over weekend to avert a default, but Japan's benchmark index still its posted first weekly gain in four weeks. The Nikkei fell 0.3 percent to 20,706.15 though it was up 2.6 percent on the week. The Nikkei volatility index rose to 18.5 percent from a 10-month low of 16.4 percent hit earlier in the week, reflecting nervousness over Gre