The sanctions are among the latest international efforts to isolate the country and follow sanctions imposed by the United Nations Security Council earlier this month.
North Korea drew a swift rebuke from the international community after successfully testing two intercontinental missiles in July, which experts say may eventually be able to deliver a nuclear warhead to the US mainland.
Japan's Chief Cabinet Secretary Yoshihide Suga said Friday, "it is extremely important to keep pressuring North Korea in coordination with US, South Korea and other countries."
Adding, "we would like to strongly urge North Korea to take concrete action towards denuclearization."
Chinese, Namibian firms targeted
The new Japanese sanctions target six companies -- four from China and two from Namibia -- and one Chinese individual and another of an unknown nationality had their Japanese assets frozen.
Tokyo has now sanctioned 72 organizations and 81 individuals for their dealings with North Korea.
These so-called "secondary sanctions," punishing those who do business with North Korea, come on the heels of similar measures levied by the US Treasury Department against Russian and Chinese entities for their dealings with North Korea on Wednesday
The United States has hoped to marshal a global coalition to isolate North Korea as part of its so-called "peaceful pressure" campaign. The hope is to put enough diplomatic and financial pressure on North Korea to bring it to the negotiating table.
Some illicit finance experts argue secondary sanctions are necessary in order to truly isolate North Korea and hinder its ability to bring in revenue.
North Korea uses the money for a host of purposes, from funding the lavish lifestyles of the country's elites to its weapons programs.
Accelerating missile program
The North Korean missile program in particular has been moving ahead at a rapid pace.
State media released propaganda photos Wednesday
showing leader Kim Jong Un inspecting missiles in development that could be fired on shorter notice than some in its current arsenal.
When it comes to the progress of Pyongyang's nuclear program, US military commanders are already operating under the assumption that North Korea has the ability to miniaturize a nuclear warhead in order place it atop a missile -- an assessment that many independent nuclear scientists share.
But South Korea's intelligence service said last month
it does not believe North Korea has perfected a stable re-entry system, which allows a warhead to survive the heat-intensive process of re-entering the Earth's atmosphere.
To pay for these programs, Pyongyang has skillfully evaded UN restrictions in order to earn cash, according to a recent report from the United Nations Panel of Experts on North Korea.
The panel found Pyongyang raised at least $270 million from commodities transactions since October last year, despite a ban on much of the trade under Security Council existing sanctions resolutions.
The report comes the same month the United Nations Security Council unanimously passed a new round of sanctions on North Korea in response to the testing of two ballistic missiles in July that experts say may be able to reach the United States.
"The United Nations Security Council just voted 15-0 to sanction North Korea. China and Russia voted with us. Very big financial impact!" US President Donald Trump tweeted after the vote.
Though China voted in favor of the UN sanctions, the country has long said it's opposed to unilateral measures to punish North Korea like the Japanese announced Friday.
Beijing views them as attempts from other countries trying to impose what it calls "long-arm jurisdiction."
"We have fulfilled and shouldered our international obligations, and our effort has been clear for all to see. If any Chinese companies or individuals are suspected of violating UN Security Council resolutions on North Korea, we will investigate and deal with them in accordance with our laws and regulations," Foreign Ministry spokeswoman Hua Chunying said at a briefing Wednesday.
Accounting for nearly 90% of Pyongyang's imports, China is by far North Korea's most important benefactor. US Presidents dating back to the Bush administration have tried to get China to use its economic leverage to rein in its unruly neighbor.
But some analysts say China has shown more of a propensity to crack down on illicit trade with North Korea recently.
"North Korea's economy is not so large that it can afford to forgo stiff economic sanctions on exports like coal, one of the mainstays of (the country's) economy," said Patrick Cronin, an Asia specialist at the Washington-based think tank Center for a New American Society.
Others worry economic pressure may not be enough, as North Korea sees the ability to successfully strike the Untied States with a nuclear weapon as the only viable way to prevent any American led attempts at regime change.
North Korea has long said unless the United States abandons its "hostile policy" toward Pyongyang, it will continue ahead with its nuclear program.
"Unless a definite end is put to the US hostile policy and nuclear threat, the DPRK will never flinch even an inch from the road of bolstering up the nuclear forces already chosen by itself," a North Korean delegation said at a disarmament conference in Geneva, North Korean state media reported Friday.