* Nikkei up 1.3 pct, biggest pct gain since Aug 14
* Exporters lifted as yen weakens for 3rd day vs dollar
* Gains by U.S. peers help Japan's tech shares
* Renesas surges on news it is buying chipmaker IDT
By Shinichi Saoshiro
TOKYO, Sept 11 (Reuters) - Japanese stocks had their best day in four weeks on Tuesday, with exporters lifted by the yen's weakening against the dollar and technology shares boosted by gains for Wall Street counterparts.
The Nikkei share average ended the day 1.3 percent higher at 22,664.69. The percentage gain was the biggest day since Aug. 14 and the close was the highest since Sept 4.
"The yen's depreciation is the key driver, with gains by the S&P 500 and Nasdaq providing additional support," said Yutaka Miura, senior technical analyst at Mizuho Securities.
"Trade friction remains a concern, but the United States is yet to activate the tariffs on $200 billion worth of Chinese imports, allowing for some short covering to kick in and lift the Nikkei," he said.
The yen slipped against the dollar for the third day, lifting exporters.
Toyota Motor Corp rose 1.6 percent, Panasonic gained 0.79 percent and Tokyo Electron was up 1.15 percent. Bridgestone Corp added 0.43 percent.
Technology shares climbed as their U.S. counterparts bounced overnight following last week's large losses, with the tech-heavy Nasdaq climbing 0.3 percent.
Renesas Electronics Corp, which announced on Tuesday it is buying U.S. peer Integrated Device Technology Inc for about $6.7 billion, jumped 4.4 percent. With the deal, Renesas aims to boost its expertise in self-driving car technologies.
Advantest Corp rose 2.51 percent, SUMCO Corp advanced 2.29 percent and Screen Holdings climbed 2.54 percent. Kyocera Corp was up 2.34 percent.
Shares of Kaga Electronics Co surged 5.41 percent after the semiconductor manufacturer announced it would buy Fujitsu Electronics from Fujitsu Semiconductor for 20.54 billion yen ($184 million).
Samco Inc, a manufacturer of equipment used to make electronic components, gained 5.17 percent after reporting strong earnings, with sales for the year through July 2018 surging 74.9 percent from the previous year to 5.47 billion yen.
Suminoe Textile co rose 5.45 percent after the company said it will repurchase 500,000 shares, or 6.6 percent of outstanding stock.
Convenience store chair operator Lawson Inc dipped 0.3 percent after saying existing store sales fell 0.2 percent in August from the previous year.
Fellow convenience store operators Seven & i Holdings Co and FamilyMart UNY Holdings Co rose 1.47 percent and 3.78 percent, respectively, after they posted increases in August same-store sales.
Of Tokyo's 33 sub-indexes, 27 closed in positive territory.
The broader Topix added 0.67 percent to 1,698.91. ($1 = 111.4300 yen) (Editing by Richard Borsuk)