* BOJ-inspired rally offset by fading hopes of more support steps
* Stronger yen undermines shares of exporters
TOKYO, Feb 3 (Reuters) - Japanese shares tumbled on Wednesday, as crude oil futures extended their recent decline and a stronger yen undermined shares of exporters.
The Nikkei stock index skidded 3.1 percent in morning trade, pulling further away from a three-week high touched on Monday.
The broader Topix and the JPX-Nikkei Index 400 both fell 3.3 percent.
"Almost every name in the N225 is down today, indicating a consensus from participants that it is time to sell," said Hiroki Allen, chief representative of Superfund Securities Japan.
The downturn also reflects fading expectations that the Bank of Japan take supportive steps after its decision to introduce negative interest rates late last week, he said.
"BOJ intervention is not likely after the negative interest rate announcement, so sellers do not expect a reversal in the declining trend," Allen said.
The BOJ's move led to two sessions of strong gains for shares, as it occurred in tandem with a short-lived recovery in crude oil prices. But fears of a global oil supply glut gained the upper hand, kindled by forecasts of milder U.S. weather, higher inventories and Iran's plans to boost exports from March.
The Topix subindex for oil and coal stocks skidded 1.7 percent.
The yen also took back some of the ground it lost after the central bank's move, strengthening for a third day. The dollar was buying 119.75 yen, down about 0.2 percent, pulling further away from a six-week high of 121.70 yen hit on Friday after the BOJ's announcement stunned markets.
The stronger currency hurt shares of transport equipment makers and machinery makers, with both subindexes losing 5.4 percent.
Concerns about earnings also weighed on investors' sentiment.
Brokerage shares also weakened, with Nomura Holdings Inc plunging 11.3 percent after the company said net profit for the October-December quarter fell 49 percent from the previous year to 35.4 billion yen ($295.84 million).
IHI Corp dropped 19 percent after the company said it expects a net loss of 30 billion yen for the fiscal year through March, instead of the previously forecast profit of 18 billion yen.
Non-bank shares shed 4.4 percent, extending their 2.5 percent drop in the last session, after rallying in the previous two days.
Defensive shares had no immunity to the broad selloff, with drugmakers dropping 1.9 percent. ($1 = 119.6600 yen) (Reporting by Lisa Twaronite, Ayai Tomisawa and Hideyuki Sano; Editing by Simon Cameron-Moore)