When you think of sumo, what’s the first word that comes to mind?

Certainly, for anyone who has ever set foot inside the ring, “painful” would be right up there.

Traditional, ritualistic, historical — there are any number of adjectives you could use to describe Japan’s national sport.

The one that perhaps best captures its essence though is “vague.”

For a sport whose history is measured in millennia, it’s incredible just how little of it is formalized.

Rugby and football have rulebooks that are hundreds of pages long and cover every imaginable scenario and action both on and off the field.

Sumo, meanwhile, has few written rules, with much of what happens on the dohyo (and indeed off it) following commonly accepted practice rather than official guidelines.

It’s an aspect of sumo that is often bewildering and frustrating for newer fans, especially those more used to western sports that have mic’d up referees explaining decisions on the field and TV shows explaining playoff permutations virtually in real time.

Imagine if soccer implemented sumo-style decision making.

Manchester United finishes fourth in the Premier League but UEFA instead awards the Champions League spot to Chelsea in fifth — maybe because the quality of their soccer was better, or perhaps because they scored more goals against tougher teams. No one knows for sure because the slots are awarded in a closed-door meeting with no explanations given thereafter. All the pundits can do is put it down to banzuke (rankings) luck.

Or what if the NFL gave officials the same powers as sumo referees and judges? Touchdown plays called back because the offensive and defensive lines hadn’t properly synchronized their breathing before the snap?

Instant replays that show one thing but are clearly interpreted the opposite way — OK, maybe the gridiron already has that part, but virtually everything that happens on the field follows clearly defined rules.

In sumo little is ever concrete, even at the highest levels. Want to earn promotion to the sport’s second highest rank? Then you need 33 wins over three tournaments — or so goes the common refrain. Tell that to Miyabiyama though. The former ozeki failed in his bid for repromotion despite earning 34 wins between March and July of 2006 with the middle (14-1) tournament including a playoff loss to an up-and-coming Hakuho lifting his first Emperor’s Cup.

Eleven years later, Takayasu got the nod with 33 wins in the ring (and one walkover victory) despite none of the tournaments including even a runner-up performance, while Goeido reached ozeki with just 32 victories.

Futahaguro became yokozuna with zero titles to his name, while Takanohana was still an ozeki with six championships to his name, none of them coming from fewer than 14 wins.

False starts, promotions, the dead body rule, hinkaku (dignity), job responsibilities — there are so many “we know it when we see it” aspects to sumo that in many other countries the whole enterprise would almost certainly collapse in recriminations and lawsuits.

In Japan, though, it works somehow and the gray areas, rather than detract from the sport, actually add to its appeal.

One of those ambiguous aspects, though, if the rumors are to be believed, could be on the verge of causing serious damage to sumo’s image.

Japan’s national sport has no Hall of Fame. The closest thing the sport has to such an honor is ichidai-toshiyori (one-generation elder) status, where a special non-transferable elder stock is created for legendary yokozuna, allowing them to continue in the association after retirement using their ring name.

To date, every yokozuna with 20 or more titles has been offered the status — apart from Asashoryu, as he was forced into retirement and left the sport entirely.

Taiho, Kitanoumi and Takanohana were stablemasters under those names while Chiyonofuji declined the honor and instead used the Jinmaku and Kokonoe name shares.

Hakuho has done enough in the ring to earn ichidai-toshiyori status twice over, but rumblings in the press suggest that he may not be offered it.

The 34-year-old’s perceived arrogance as well as an occasional undignified extra shove or elbow blast has some claiming that he isn’t worthy of the honor.

Make no mistake — failure to award Hakuho one-generation elder stock would be a massive own goal for the Japan Sumo Association and leave it open to claims of discrimination.

Hakuho may not be the sport’s most popular rikishi, but as with Tom Brady in football, that apathy mostly stems from boredom at seeing him succeed too often rather than anything concrete the man himself has done.

Suggesting Hakuho doesn’t deserve ichidai-toshiyori status is as ridiculous as claiming Brady doesn’t belong in the Hall of Fame.

Indeed Hakuho has a far greater claim, as while football is a team game and you can point to all kinds of factors that influence success, sumo is an individual sport where every win is solely the responsibility of the rikishi himself.

Hakuho may have played the black hat cowboy role over the past few years, but for the bulk of his career he was the hero with impeccable dignity who dragged sumo through some of its darkest years.

A student of the sport, he has shown time and again he understands both his role in sumo and that of a yokozuna in general.

When leading people in a banzai cheer is the worst thing you have done (in a sport that has struggled with violence, drug and match-fixing scandals), you’ve been pretty much an angel.

Unlike past ichidai-toshiyori recipients, he hasn’t illegally brought guns into Japan and given them to gangsters or spent most of his career embroiled in tabloid scandals.

As one former top-level wrestler whose family has been involved in sumo for generations put it to me the other day, “There are rumors in the public sphere but are there are no stablemasters or rikishi who think like that right? He is No. 1 in titles and No. 2 in consecutive wins and kept the sumo association going when its popularity was low. There is no reason he shouldn’t get it.”

That was more or less the opinion of every single person connected to sumo that I talked to over the past few days. Online votes and columns may show about 10-15 percent of people against the idea but in sumo itself Hakuho deserving the honor seems to be the consensus opinion.

Let’s hope the JSA listens to the experts.