Japanese Q4 GDP 2017 data is here from earlier:

This via Barclays (in summary, bolding mine)

Q4 GDP revised up, but our economic outlook unchanged

  • Q4 real GDP growth was revised sharply upward to 0.4% q/q (1.6% saar) in the second preliminary data from an initial 0.1% q/q (0.5% saar). This was an upside surprise exceeding the Bloomberg median estimate (1.0% q/q saar).
  • The revision was due primary to an upward adjustment to private inventory investment. Although this will mean a drag on GDP growth in Q1, it does not change our current economic assessment.

And, Barclays looking ahead:

GDP outlook for Q1 2018 onward:

  • GDP growth may slow from Q4 to Q1 due to a slump in housing investment and drag on private consumption from cold weather.
  • Whether growth remains positive for a ninth consecutive quarter will likely depend on private consumption from February onward.

A bit more detail if you are after it:

Q4 real GDP: Revised up

  • reflected a large upward adjustment to private inventory investment
  • in addition to an upward revision to private capex
  • upward revisions to private housing investment, public fixed capital formation and government final consumption

Q1 18 real GDP

forecast real GDP growth of 1.4% q/q saar for Q1

However, downside risks are mounting:

  • 1) Production appears likely to decrease by 1-2% q/q in Q1 (Q4: 1.8% q/q);
  • 2) the upward revision to private inventory investment in Q4 will be a drag on growth in Q1;
  • 3) there is an increasing risk that real private consumption will undershoot our forecast (0.2% q/q) due to the cold snap;
  • and 4) private housing investment dropped sharply in January (-8.6% m/m versus -2.7% in December)).

The consumption activity index, released on 7 March, rose a real 0.4% m/m in January (December: -1.0% m/m), the first gain in two months. This was a surprisingly strong reading given the somewhat steep drop in retail sales (-1.8% m/m in January, 0.9% m/m in December) due in part to the cold snap. However, the cold snap may also have impacted consumption activity in early February, suggesting data from that month will also warrant attention. Our forecast for growth exceeding potential in Q2 is unchanged