* Euro gains on yen, takes other yen pairs with it
* Yen fall aided by speculation over investment trust flows
* Bias toward risk-taking on upbeat stocks, earnings -trader
* Kiwi near 9-month high vs dollar
By Kaori Kaneko
TOKYO, July 23 (Reuters) - The yen dropped sharply across the board on Thursday, undercut by expectations of investment trust flows out of Japan this week and as gains in the euro set off automatic sell orders in other yen pairs.
The Australian and New Zealand dollars touched their highest in three weeks against the Japanese currency, climbing about 1 percent on the day, while the dollar also gained 0.7 percent.
One trader said the yen's move down began with euro buying early in the Asian session, which then triggered stop-loss buy orders on the single European currency and the dollar.
The market is also watching closely for yen selling related to launches this week of Japanese investment trusts which will invest in overseas assets and foreign currencies.
"Speculation of solid demand for investment trusts prompted investors to sell the yen," said a trader at a European bank.
"Also, investors unwound dollar short positions accumulated against the yen," he said.
UBS is set to launch 10 investment trusts or "toshin" on Friday with subscription ceilings totalling 1.2 trillion yen ($12.8 billion) that will invest in global bonds.
Such investment funds do not always gather as much funds as the ceiling allows, and sometimes fall well short, but the market watches them carefully for clues on the yen's direction.
UBS will give investors a choice of currencies, including the yen, the Australian dollar, the Brazilian real, the South African rand and the Turkish lira.
Nomura Asset Management also launches an investment trust on Friday with a subscription ceiling of 100 billion yen which will focus on emerging market stocks.
The dollar rose 0.7 percent to 94.35 yen and the euro climbed 1 percent to 134.43 yen, with the day's peak at 134.53 on trading platform EBS. One trader said buy orders at 133.60 yen had helped propel it higher early on.
The European currency edged up 0.2 percent to $1.4248, below a seven-week high of $1.4278 hit on Tuesday.
The dollar index, a gauge of the greenback's performance against six major currencies, was holding above this week's seven-week low of 78.563.
"The overall bias is toward risk-seeking, as the stock markets have shown a strong run-up and the Fed has clearly stated it will continue its easy policy, which was a relief for the market," said Tsutomu Soma, a senior manager of foreign securities at Okasan Securities.
Traders said Federal Reserve Chairman Ben Bernanke provided little market-moving news on Wednesday in testimony to the Senate Banking Committee. Bernanke reiterated that the U.S. economic outlook was improving but supportive policies would be necessary for a while to prevent rising joblessness from sapping economic recovery.
Risk appetite has been improving in recent days, fuelled by strong quarterly results from some large banks including Goldman Sachs, although it can be fickle with gains reversing the next day.
"Optimism has emerged on recent relatively solid corporate earnings from the U.S. But since the currency market has priced that in, it is looking for stronger leads," said Yousuke Hosokawa, Treasury Department senior manager at Chuo Mitsui Trust and Banking.
Among commodity-related currencies, the New Zealand dollar rose 0.3 percent to $0.6607, after hitting its highest point in nine months above $0.6630 the previous day.
The Australian dollar firmed 0.5 percent to $0.8195 although it was still below Wednesday's six-week high of $0.8214. (Additional reporting by Aiko Hayashi; Editing by Joseph Radford)