A camera viewfinder shows value of the Nikkei 225 at the Tokyo Stock Exchange (TSE) after market opens in Tokyo, Japan October 2, 2020. REUTERS/Kim Kyung-Hoon 

Chart showing Nikkei 225 index for the last 30 years. embed code and instructions: https://reut.rs/2IqBvrK 

A man walks past an electronic board showing Japan's Nikkei 225 outside a brokerage in Tokyo, Japan January 12, 2016. Japan's Nikkei fell 2.7 percent after a market holiday on Monday, closing at its lowest in nearly a year, while U.S. stock mini futures were in the red pointing to a weak start. REUTERS/Toru Hanai

Employees of the Tokyo Stock Exchange (TSE) work at the bourse in Tokyo August 26, 2015. Asian stocks fell on Wednesday as investors feared fresh rate cuts in China would not be enough to stabilize its cooling economy or halt a collapse in its stock markets. REUTERS/Yuya Shino 

A man walks past the logo of Japan Exchange Group Inc. at the Tokyo Stock Exchange (TSE) in Tokyo August 26, 2015. Asian stocks fell on Wednesday as investors feared fresh rate cuts in China would not be enough to stabilize its cooling economy or halt a collapse in its stock markets. REUTERS/Yuya Shino 

A man looks at an electronic board showing Japan's Nikkei average and related indices at the Tokyo Stock Exchange (TSE) in Tokyo August 26, 2015. Japanese stocks bounced slightly in another volatile session on Wednesday morning, but sentiment remained fragile despite aggressive policy easings by Beijing as a collapse in Chinese stocks threatened to wreak havoc on a stumbling economy. REUTERS/Yuya Shino

A man looks at an electronic board showing Japan's Nikkei average and related indices at the Tokyo Stock Exchange (TSE) in Tokyo August 26, 2015. Japanese stocks bounced slightly in another volatile session on Wednesday morning, but sentiment remained fragile despite aggressive policy easings by Beijing as a collapse in Chinese stocks threatened to wreak havoc on a stumbling economy. REUTERS/Yuya Shino

An employee of the Tokyo Stock Exchange (TSE) works at the bourse in Tokyo August 26, 2015. Japanese stocks bounced slightly in another volatile session on Wednesday morning, but sentiment remained fragile despite aggressive policy easings by Beijing as a collapse in Chinese stocks threatened to wreak havoc on a stumbling economy. REUTERS/Yuya Shino

An employee of the Tokyo Stock Exchange (TSE) works at the bourse in Tokyo August 24, 2015. Asian stocks slumped to 3-year lows on Monday as a slump in Chinese equities gathered pace, hastening an exodus from riskier assets as fears of a China-led global economic slowdown churned world markets. REUTERS/Toru Hanai

A woman holding an umbrella walks past an electronic board showing Japan's Nikkei 225 outside a brokerage in Tokyo, July 8, 2015. Japanese stocks tumbled on Wednesday in their biggest drop in more than a year, as fears grew that a relentless selloff in Chinese shares could ripple through its economy and hurt Japanese companies exposed to the Asian giant. REUTERS/Toru Hanai

People are reflected in an electronic board displaying Japan's Nikkei share average outside a brokerage in Tokyo April 23, 2015. For market indices, round numbers have little more than symbolic meaning. Even so, the Nikkei 225 index's first close above 20,000 in 15 years is a significant benchmark for Japanese stocks. REUTERS/Toru Hanai 

Men are reflected on an electronic board displaying Japan's Nikkei share averages outside a brokerage in Tokyo April 23, 2015. For market indices, round numbers have little more than symbolic meaning. Even so, the Nikkei 225 index's first close above 20,000 in 15 years is a significant benchmark for Japanese stocks. REUTERS/Toru Hanai 

Visitors look at the bourse at the Tokyo Stock Exchange in Tokyo March 3, 2014. Japan's Nikkei average slid more than 2 percent to a 1-1/2-week low on Monday as escalating tensions in Ukraine sparked risk aversion and a stronger yen roughed up exporters like Toyota Motor Corp and Canon Inc. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS) 

A visitor walks past logos at the Tokyo Stock Exchange in Tokyo June 13, 2013. Japan's Nikkei share average dived back into bear market territory on Thursday, dipping to levels seen before the central bank's sweeping monetary policy stimulus in early April, as the yen rebounded, sending shares of exporters tumbling. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS) 

Pedestrians pass by an electronic board displaying various countries' share prices, seen through car windows in Tokyo June 7, 2013. Japan's Nikkei share average sank into bear territory on Friday before recouping some of its losses on expectations that the country's $1 trillion public pension fund would ramp up its buying of equities. REUTERS/Yuya Shino (JAPAN - Tags: BUSINESS TPX IMAGES OF THE DAY) 

A visitor is seen through the logo of Tokyo Stock Exchange in Tokyo May 24, 2013. Japan's Nikkei stock average turned positive in a volatile session on Friday afternoon after the previous session's 7.3 percent plunge. The Nikkei was up 1 percent at 14,626.91 by 0543 GMT after shedding as much as 3.5 percent at one point earlier in the afternoon. The benchmark ended the morning session 2.7 percent higher. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS) 

Visitors watch an electronic board showing Japan's Nikkei prices and related indexes at Tokyo Stock Exchange (TSE) in Tokyo April 24, 2013. Japan's Nikkei share average climbed to its highest level in nearly five years on Wednesday on robust U.S. company earnings and as the yen resumed its downward slide towards 100 to the dollar. By the midday break, the Nikkei advanced 1.3 percent to 13,703.62 after earlier tapping 13,745.71, its highest level since June 2008. The yen hit a low of 99.77 against the dollar on the day, within striking distance of 100. REUTERS/Yuya Shino (JAPAN - Tags: BUSINESS) 

A man walks past an electronic screen displaying the Nikkei share average as cherry blossoms are in full bloom outside a brokerage in Tokyo March 22, 2013. Japan's Nikkei average shed 2.4 percent on Friday as concerns mounted that Cyprus may be forced to exit the euro zone after the European Union gave the island's government until Monday to raise the billions of euros it needs to secure a bailout. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS) 

A visitor takes pictures in front of an electronic board showing stock prices at Tokyo Stock Exchange (TSE) in Tokyo March 19, 2013. Japan's Nikkei average rebounded 2 percent at the midday break on Tuesday, regaining some ground lost in the previous session after a controversial bailout proposal for Cyprus raised concerns about the stability of Europe's banking sector. The Nikkei gained 246.55 points to 12,467.18 after sliding 2.7 percent on Monday, its biggest one-day drop in 10 months. REUTERS/Yuya Shino (JAPAN - Tags: BUSINESS) 

People shake hands in front of an electronic board displaying a graph of Japan's Nikkei share average and other market indices outside a brokerage in Tokyo October 30, 2012. Japan's Nikkei average fell 1 percent to a two-week closing low on Tuesday after the Bank of Japan eased monetary policy by increasing the size of its asset buying and lending programme by $138 billion, largely as expected. REUTERS/Yuriko Nakao (JAPAN - Tags: BUSINESS) 

A visitor looks at his mobile phone in front of monitors displaying market indices at the Tokyo Stock Exchange in Tokyo July 13, 2012. Japan's Nikkei share average slipped on Friday morning after a fall in Wall Street shares and as the market braces for Chinese GDP data that is likely to show a slowdown in the world's second-biggest economy. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS) 

Cherry blossoms are seen in front of the Tokyo Stock Exchange building in Tokyo April 11, 2012. The Tokyo Stock Exchange and Daiwa Securities Group have agreed with Myanmar's central bank to set up a securities exchange in Myanmar, Japan's public broadcaster NHK reported on Wednesday. They aim to establish a securities exchange by 2015 and help the newly emerging economy develop financial infrastructure, NHK reported. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS POLITICS) 

An employee of Tokyo Stock Exchange dressed in ceremonial kimono works at the bourse after its New Year opening ceremony in Tokyo January 4, 2012. Japan's Nikkei average rose 1.2 percent to hit a three-week closing high on Wednesday after upbeat economic data from the United States and China eased worries over the health of the global economy. REUTERS/Kim Kyung-Hoon (JAPAN - Tags: BUSINESS) 

Attendants clap during the New Year opening ceremony to wish success for Japan's stock market at the Tokyo Stock Exchange (TSE) in Tokyo January 4, 2012. The benchmark Nikkei average rose 1.4 percent and the broader Topix gained 1.7 percent on Wednesday. REUTERS/Kim Kyung-Hoon (JAPAN - Tags: BUSINESS ANNIVERSARY) 

Women dressed in ceremonial kimonos pose in front of an electronic board showing stock prices at the Tokyo Stock Exchange's (TSE) New Year opening ceremony in Tokyo January 4, 2012. The benchmark Nikkei average rose 1.4 percent and the broader Topix gained 1.7 percent on Wednesday. REUTERS/Kim Kyung-Hoon (JAPAN - Tags: BUSINESS ANNIVERSARY) 

People are reflected on a stock quotation board displaying the Nikkei share average outside a brokerage in Tokyo March 28, 2011. Japan's Nikkei fell 0.4 percent as workers continued to battle to stem radiation leaks at the crippled Fukushima nuclear plant, and more dead were pulled from the rubble in the country's northeast, which was devastated by a massive quake and tsunami on March 11. REUTERS/Toru Hanai (JAPAN - Tags: DISASTER BUSINESS) 

JAPAN-QUAKE/MARKET - Timeline of events plotted against movements in Japan's Nikkei 225 since Friday's earthquake. (SIN04) 

JAPAN-QUAKE/MARKET - Timeline of events plotted against movements in Japan's Nikkei 225 since Friday's earthquake. (SIN04) 

Employees of the Tokyo Stock Exchange (TSE) work at the bourse in Tokyo March 14, 2011. Japan's Nikkei average extended losses and fell 3.9 percent to 9,851.06 in early trade on Monday as the market gauges the effects of last week's earthquake and tsunami. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS DISASTER) 

An employee of the Tokyo Stock Exchange (TSE) works at the bourse in Tokyo March 14, 2011. The Nikkei share average was down 5 percent soon after Tokyo's financial markets opened on Monday, as the market gauged the effects of last week's earthquake and tsunami. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS DISASTER) 

Employees of the Tokyo Stock Exchange (TSE) work at the bourse in Tokyo March 14, 2011. The Nikkei share average was down 5 percent soon after Tokyo's financial markets opened on Monday, as the market gauged the effects of last week's earthquake and tsunami. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS DISASTER) 

Employees of the Tokyo Stock Exchange (TSE) work at the bourse in Tokyo March 14, 2011. The Nikkei share average was down 5 percent soon after Tokyo's financial markets opened on Monday, as the market gauged the effects of last week's earthquake and tsunami. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS DISASTER) 

Employees of the Tokyo Stock Exchange (TSE) work at the bourse in Tokyo March 14, 2011. Japan's Nikkei average extended losses and fell 3.9 percent to 9,851.06 in early trade on Monday as the market gauges the effects of last week's earthquake and tsunami. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS DISASTER) 

Women dressed in ceremonial kimonos pose in front of an electronic board showing stock prices at the Tokyo Stock Exchange's (TSE) New Year opening ceremony in Tokyo January 4, 2011. REUTERS/Yuriko Nakao (JAPAN - Tags: BUSINESS IMAGES OF THE DAY) 

Women dressed in ceremonial kimonos clap to wish for success in the coming year during the Tokyo Stock Exchange's (TSE) New Year opening ceremony in Tokyo January 4, 2011. REUTERS/Yuriko Nakao (JAPAN - Tags: BUSINESS) 

A man is reflected in a stock index board outside of a brokerage in Tokyo June 7, 2010. Japan's Nikkei average fell more than 3 percent on Monday as investors, spooked by debt woes in Hungary and the euro's fall to a more than eight-year low against the yen, sold shares across the board. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS EMPLOYMENT IMAGES OF THE DAY) 

A visitor walks past a sign of the Tokyo Stock Exchange (TSE) at the TSE in Tokyo April 28, 2010. Japan's Nikkei average slid 2.7 percent on Wednesday, hit by downgrades for Greece and Portugal's credit ratings that sent Wall Street tumbling. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS EMPLOYMENT) 

A man is reflected on a stock market board in a business district in Tokyo April 26, 2010. Japan's Nikkei average climbed 2 percent on Monday, breaking above resistance at the level of its 25-day moving average, as exporters such as Honda Motor gained after a Wall Street climb to a 19-month high. REUTERS/Issei Kato (JAPAN - Tags: BUSINESS IMAGES OF THE DAY) 

JAPAN-TSE/LAUNCH - Chart detailing Japan's Nikkei index and trading volume statistics since 1989. The Tokyo Stock Exchange launched a new and faster trading system on Monday that allows it to handle much larger trade volumes, making it on par with rivals such as New York and London. RNGS. (SIN04) 

JAPAN-TSE/LAUNCH - Chart detailing Japan's Nikkei index and trading volume statistics since 1989. The Tokyo Stock Exchange launched a new and faster trading system on Monday that allows it to handle much larger trade volumes, making it on par with rivals such as New York and London. RNGS. (SIN04) 

A worker stands in front of the logo of Tokyo Stock Exchange after the opening ceremony of the stock market and launching of the "Arrowhead" system at its headquarters in Tokyo January 4, 2010. The Tokyo Stock Exchange launched its $145 million "Arrowhead" system on Monday, as Asia's biggest bourse targets a dramatic increase in speed to revive its business and reputation. REUTERS/Kim Kyung-Hoon(JAPAN - Tags: BUSINESS IMAGES OF THE DAY) 

Kimono clad women pose at the opening of the stock market and launching "Arrowhead" system at the headquarters of Tokyo Stock Exchange (TSE) January 4, 2010. The Tokyo Stock Exchange launched its $145 million "Arrowhead" system on Monday, as Asia's biggest bourse targets a dramatic increase in speed to revive its business and reputation. REUTERS/Kim Kyung-Hoon(JAPAN - Tags: BUSINESS) 

A man passes by a logo of the Tokyo Stock Exchange at the bourse in Tokyo December 29, 2009. Long derided as one of the world's slowest major stock exchanges, the Tokyo Stock Exchange is rolling out a new platform to give it a much-needed speed infusion and defend itself from a global and domestic rivals. REUTERS/Yuriko Nakao (JAPAN - Tags: BUSINESS EMPLOYMENT IMAGES OF THE DAY) 

A staff of the Tokyo Stock Exchange works at the centre where it monitors stock trading, at its headquarters in Tokyo April 21, 2009. Evidence of more pain inflicted by the global financial crisis on banks, manufacturers and whole economies dampened hopes for a speedy recovery and snapped a six-week global stocks rally. REUTERS/Kim Kyung-Hoon (JAPAN BUSINESS) 

A stock quotation board is reflected on a puddle as a man waits at a traffic crossing in Tokyo April 14, 2009. Japan's Nikkei stock average slipped 0.9 percent on Tuesday as worries over General Motors spurred investors to lock in profits on auto shares, while banks rose on upbeat results from U.S. financial stocks. REUTERS/Issei Kato (JAPAN BUSINESS IMAGE OF THE DAY TOP PICTURE TRANSPORT) 

A woman carrying a bouquet of flowers as she walks past a stock index board outside of a brokerage in Tokyo April 2, 2009. The benchmark Nikkei average rose 3 percent and the broader TOPIX was 3.2 percent higher as of the midday break on Thursday. REUTERS/Kim Kyung-Hoon (JAPAN BUSINESS) 

Pedestrians are reflected on an electronic board displaying an arrow under characters reading "Nikkei" outside a brokerage in Tokyo March 13, 2009. Japan's Nikkei average rose 5.2 percent on Friday to its biggest weekly gain in over 3 months on hopes for the U.S. economy after data showed retail sales stabilising and Bank of America reported a return to profit. REUTERS/Yuriko Nakao (JAPAN BUSINESS) 

A stock index board is seen through a video camera's view finder at the Tokyo Stock Exchange in Tokyo March 2, 2009. Japan's Nikkei stock average slid 3.2 percent on Monday, with Mitsubishi UFJ Financial Group and other banks sinking on fears about their U.S. peers, while exporters slipped on worry about the U.S. economy. REUTERS/Issei Kato (JAPAN) 

A stock dealer yawns during trading at the Tokyo Stock Exchange in Tokyo March 2, 2009. Japan's Nikkei stock average slid 3.2 percent on Monday, with Mitsubishi UFJ Financial Group and other banks sinking on fears about their U.S. peers, while exporters slipped on worry about the U.S. economy. REUTERS/Issei Kato (JAPAN) 

A security guard walks at the Tokyo Stock Exchange in Tokyo January 13, 2009. The Nikkei average share slid 4.3 percent on Tuesday with Sony Corp tumbling on news of an operating loss and camera maker Canon Inc dropping on discouraging remarks about sales by its chairman. REUTERS/Toru Hanai (JAPAN) 

An employee of Tokyo Stock Exchange, dressed in a ceremonial kimono, is seen at its trading room in Tokyo January 5, 2009. Japan's Nikkei average rose 1.5 percent on Monday, the first trading day of 2009, after Wall Street rallied on Friday to its highest levels since early November on hopes 2009 will be a better year. REUTERS/Kim Kyung-Hoon (JAPAN) 

Officers and employees of securities companies cast shadows on a sign of the Tokyo Stock Exchange (TSE) during a ceremony marking the end of trading in 2008 at the TSE in Tokyo December 30, 2008. Tokyo shares looked set to book their worst year ever in 2008, with the Nikkei benchmark average losing 0.4 percent on Tuesday, pressured after Wall Street declined on economic worries and the threatened failure of a chemical firm takeover. REUTERS/Issei Kato (JAPAN) 

Stock dealers conduct the final trading of the year at the Tokyo Stock Exchange in Tokyo December 30, 2008. Tokyo shares looked set to book their worst year ever in 2008, with the Nikkei benchmark average losing 0.4 percent on Tuesday, pressured after Wall Street declined on economic worries and the threatened failure of a chemical firm takeover. REUTERS/Issei Kato (JAPAN) 

People walking into the Tokyo Stock Exchange in Japan November 17, 2008. REUTERS/Stringer (JAPAN) 

The Tokyo Stock Exchange is seen in Tokyo November 17, 2008. REUTERS/Stringer (JAPAN) 

The logo of the Tokyo Stock Exchange is seen in Tokyo November 20, 2008. Asian markets suffered the same battering that drove U.S. and European stocks to their lowest levels in over 5 years on Wednesday. Japan's Nikkei tumbled 6.9 percent, while the MSCI All-Country World Index hit its lowest level since May 2003, dragged down by Asian shares. REUTERS/Kim Kyung-Hoon (JAPAN) 

People are reflected on a board displaying the Nikkei share average outside a brokerage in Tokyo
November 4, 2008. Japan's Nikkei average rose 5.9 percent on Tuesday, boosted as exporters such as Toyota Motor Corp climbed, with electronics maker Panasonic jumping after sources said it was planning to take over Sanyo Electric. REUTERS/Kim Kyung-Hoon (JAPAN) 

A staff member smiles at the Tokyo Stock Exchange November 4, 2008. Japan's Nikkei index rose nearly 6 percent on Tuesday, playing catch-up after a holiday, but other stock gains were tame after reports pointed to a shrivelling U.S. economy ahead of the presidential election. REUTERS/Kim Kyung-Hoon (JAPAN) 

A man attends a stock market investment class at the Tokyo Stock Exchange in Tokyo October 22, 2008. Japan's Nikkei average slid 6.8 percent on Wednesday to its lowest close in a week, battered down as Sony Corp and other exporters fell after the yen rose against the euro and worries about the global economy deepened. REUTERS/Kim Kyung-Hoon (JAPAN) 

A staff of the Tokyo Stock Exchange is seen in its trading room after afternoon trading in Tokyo October 22, 2008. Japan's Nikkei average slid 6.8 percent on Wednesday to its lowest close in a week, battered down as Sony Corp and other exporters fell after the yen rose against the euro and worries about the global economy deepened. REUTERS/Kim Kyung-Hoon (JAPAN)