"If the conditions stay the same, I don't think really low scores are possible," said Hasegawa, who has made the cut in three Japan Golf Tour events this year. "The key is knowing which holes to attack and which holes to be conservative."
Dou Zecheng, the first-round leader, had a 75 and was one shot behind along with Lee Soo-min of South Korea (70) and Kazuya Koura of Japan, whose 69 was the low score of the second round.
Hasegawa is not the only player at Nanshan International who has experience on the pro tours. Lee tied for second last week with Rory McIlroy in the Korea Open. He had the lead to himself until missing short par putts on the last two holes.
"Everything was going so well, but I kind of messed up at the end," Lee said. "But I came here with the aim of winning the tournament and it's just about trying to be comfortable."
Among those within three shots of the lead were a pair of Australians Oliver Goss, who already has earned a trip to the Masters as the U.S. Amateur runner-up, and Brady Watt, a semifinalist at the U.S. Amateur.
The cut was at 17-over 159, eight shots higher than the previous record for the Asia-Pacific Amateur. Sixty-one players qualified for the final two rounds.