After the way in which the unprecedented All Blacks coaching appointment process played out prior to the Rugby World Cup, Foster had every right to switch allegiance and pursue the prospect of joining another test nation -as two of his offsiders have done.
Foster is tight with former All Blacks assistant turned Wallabies head coach Joe Schmidt and experienced forwards mentor Mike Cron, having worked alongside both with the national team.
Behind the scenes, there must have been conversations and temptations to get the band back together - only this time in green and gold.
Despite the grudge Foster bears against New Zealand Rugby hierarchy for his exit, the thought of coaching against the All Blacks or, more specifically, the cohort of elite players he earned trust from, would have been a step too far at this point.
That’s not to say Foster won’t ever coach against the All Blacks. But, as a deeply loyal character, he may have felt uncomfortable using his extensive dossier and close ties with those established test players to then plot their downfall.
With up to 15 of the All Blacks’ 23-man squad who lost the World Cup final by one point to South Africa in line to return for Scott Robertson’s first test in July, Foster linking with the Wallabies would certainly have sparked concern within the New Zealand Rugby halls of power.
The optics of Schmidt, an All Blacks assistant for little over a year, and Foster, who savoured a 12-year stint in that environment, are distinctly different.
Foster never shied away from his desire to continue coaching. It was a matter of when and where, not if, he would return.
With international head coaching opportunities limited at this stage, he could have opted to seek a post in Europe where movement is again heating up.
From a lucrative salary, scrutiny and pressure perspective, though, Japan is the ideal coaching destination.
Week-to-week the pressure to perform in England, Ireland and France, not only domestically but to reach European rugby’s top eight Champions Cup knockout stages, is relentless. Don’t achieve those metrics and coaches are soon turfed out.
Ian Foster's four-year tenure in charge of the All Blacks delivered a 69.5 per cent win record. Photo / Getty Images
While Foster concluded his All Blacks tenure exceeding all external expectations by coming within one missed penalty, one lower tackle, of World Cup glory, his four-year term that featured a 69.5 per cent win record was a tumultuous, emotionally draining ride.
From the brink of the axe to the verge of the ultimate victory, few, if any, coaches traversed such extremes in the same cycle.
Five months on from stepping away from that intense spotlight, diving into the European coaching pressure cooker, albeit at domestic level, would take a toll on anyone, let alone someone with the scars Foster carries.
The Japanese League One competition is not without expectations, of course. Big budgets - leading clubs spend $30 million annually on all operating costs - demand results.
But a comparatively short season, which allows prolonged stints at home, significantly less public and media scrutiny and some of the world’s best salaries adds up to highly desirable coaching positions.
At Toyota Verblitz, Foster will enjoy the familiarity of rejoining former All Black Aaron Smith, a healthy playing roster budget and, more importantly from a stability perspective, support from long-time confidant Sir Steve Hansen, the club’s director of rugby for the past four years.
Tick, tick, tick.
Make a success of this next move, and Foster could become the latest New Zealand coach to set up camp in Japan.
For the past decade, Robbie Deans has made bank and captured multiple titles with the Wild Knights to consistently set standards there.
Whether Foster can guide Toyota to those heights remains to be seen but after his turbulent ride with the All Blacks he could not ask for a better next coaching post.
