Two-time Olympic medalist Hiroyasu Shimizu took a big step toward his sixth national sprint championships title, taking the halfway lead after two opening-day races Wednesday.
Shimizu won both the 500 and 1,000 meters to take control of the men's competition while defending champion Aki Tonoike topped the women's standings going into Thursday's races at Makomanai Ice Arena.
In the men's 500, Shimizu clocked 36.62 seconds -- well off his world record of 34.32 -- in the first of four races at the championships.
High school student Joji Kato took second in 36.65 and Tomonori Kawata third in 37.13.
Shimizu then came home first in 1:14.41 in the 1,000 to stand atop the men's standings on 73.825 points, holding a healthy 0.85-point advantage over Kato.
Tonoike grabbed the overall lead with 81.765 after finishing sixth in the 500 and second in the 1,000.
Yukari Watanabe won the women's 500 in 40.14, followed by Tomomi Okazaki and Sayuri Osuga. Maki Tabata was fastest in the 1,000 in 1:21.21.