The Syrian crisis and sluggishness in emerging economies, major topics at the two-day Group of 20 summit that wrapped up Friday in St. Petersburg, Russia, are two issues Japan can't afford to regard with indifference.

They could weigh on Japan's economy, which has shown signs of emerging from nearly two decades of deflation on the back of Prime Minister Shinzo Abe's economic policies dubbed "Abenomics," centering on aggressive monetary easing and massive fiscal spending.

As the moment draws near for Abe's final decision on whether to carry out the sales tax hike as scheduled next year, many observers want to see how he can fulfill his pledge to simultaneously bolster the economy and improve the government's precarious fiscal health.