Tokyo stocks closed lower to end a six-day rally Friday as investors tried to lock in profits before the weekend, according to dpa. The Nikkei 225 Stock Average dipped 51.67 points, or 0.28 per cent, to close at 18,188.63. The broader Topix index of all first-section issues was also down 11.39 points, or 0.64 per cent, to close at 1,777.99. For the week, Nikkei rose 1.21 per cent, and Topix also went up 0.28 per cent. On currency markets at midday (0300 GMT), the dollar was quoted at 123.94-99 yen, up from Thursday's 5 pm quote of 123.68-71 yen. The euro was quoted at 1.3387-90 dollars, up from Thursday's 5 pm quote of 1.3378-81 dollars, and at 165.95-166.00 yen, up from 165.49-53 yen.