I have recently written an article that analyses the players Jamie Joseph will be relying on for success during this year’s November tests and next year’s World Cup based on the number of caps players have.

Inspired by The 1014 Rugby Depth video, this article analyses the same question from a different angle by quantifying the depth (not caps) Joseph and his staff have built during this World Cup cycle. Backend and frontend codes I used to develop this can be found here.

What Japan Depth Looks Like


My chart is slightly different from The 1014 Depth Chart. I have grouped together the Second and Back Row, the 10-12-13 channel, and the Back Three. Because players such as Kazuki Himeno, Harumichi Tatekawa and Kotaro Matsushima are versatile in these groups of positions respectively.

Also, I have only displayed the top three options for each position because a typical World Cup squad can only fit around three options for each position. Notice the bar for the number 9 position reaches 100%. This is because Joseph has only used three different halfbacks so far against Tier 1 or 2 opposition.

Furthermore, the top two players in the back three with the most game time are regarded as the first choice players because typically, two play for 80 minutes (first choice players) and another two play for less than 80 minutes (second choice players). The same logic applies to the 10-12-13 channel and the Second and Back Rowers.

Lastly, the Asian Rugby Championship matches have been excluded because of two main reasons. Firstly, Japan’s opposition were nations that traditionally don’t qualify for the Rugby World Cup. Secondly, many of Japan’s national side players were unavailable due to Sunwolves duties at the time. The 2016 June tests have also been omitted because those tests were played before Joseph started coaching Japan.

First observation:

Before I used the cleaned data to visualize the depth chart, I realised that the four players who have been capped in all of the tests used were Horie (Hooker), Mafi (Number 8), Tamura (Fly Half) and Tanaka (Scrum Half). Also, Kotaro Matsushima (Fullback) has been capped in all apart from one of these tests. Notice that these are the players from the spine positions. This definitely supports Gareth and Steve’s theory of building the spine of the team before building the other positions.

Loosehead Prop:

Inagaki: 62%
Ishihara: 14%
Nakatani: 13%

Loosehead prop has the best depth distribution out of the ungrouped positions. Also, two of the three Loosehead Props who has played for the Sunwolves in all three seasons, Masataka Mikami (33 test caps) and Koki Yamamoto (5 test caps) are not on this list.

The other Loosehead Prop to play for the Sunwolves in all three seasons is the first choice for Japan, Keita Inagaki. So on top of the depth that has been built in this position, the first choice player has gained a lot of high-level rugby experience. Hats off to Japan and the Sunwolves’ coaching staff for their successful job here.


Horie: 83%
Niwai: 11%
Sakate: 4%

This is definitely a position Joseph has taken some risk. Shota Horie has played more minutes than any other player in the tight-five, making hooker have the highest proportion of minutes played by the first-choice option than any other position on the chart.

With a lot of risk in such an important position (especially for set pieces), Horie is definitely the player Japan cannot afford to lose for the World Cup.

Tighthead Prop:

Player Game minutes proportion Top League team
Koo 37% Honda Heat
Ito 21% Yamaha Jubilo
Asahara 18% Toshiba Bravelupus
Valu 10% Panasonic Wildknights
Hatakeyama 6% Suntory Sungoliath
Watanabe 5% Kobelco Steelers
Yamaji 2% Canon Eagles

It won’t be accurate enough to analyse just the top three players for tighthead prop. Because seven different players have been used by Joseph for this position against Tier 1 or 2 opponents. So we still don’t have a clear picture of which tightheads are pencilled in Joseph’s team list for the World Cup.

But on a positive note, not two of them play for the same Top League team. So competition between these players to perform in this last Top League tournament before the World Cup will be high. Which overall will be a bonus for the national team. Scrum coach for Japan and Sunwolves, Shin Hasegawa will have a close eye on this year’s Top League tournament to select his cornerstones for next year.

Second and Back Row:

Rank Game minutes proportion Players
First choice 57% Mafi, Leitch, Himeno, Helu
Second choice 24% Nunomaki, Van der Walt, Yatabe, Kajikawa
Third choice 11% Ilaua, Matsuhashi, Tokunaga, Anisi

The biggest take from this section is that the three players with the most minutes against Tier 1 or 2 opponents under Joseph, which are Mafi, Leitch and Himeno; none of them are second rowers. Although Himeno can play lock, at a height of just 1.88m, his most preferred position is at flanker. The international retirement of locks Luke Thompson and the ageing 40-year-old veteran Hitoshi Ono who have both played in the last three World Cups has definitely caused Joseph selection problems at lock. Luke Thompson had to even come out of international retirement for one test last year due to a lack of locks in the squad.

The only lock from the 2015 Rugby World Cup who has been playing under Joseph is Shinya Makabe. He has had very little game time under Joseph and thus did not make it on the list of 12 players above. I suspect Joseph is minimising his game time for player welfare reasons. This is because he has been a key player for both the Sunwolves and Suntory in the last three seasons. But when he is given the opportunity to start, he has made massive contributions. This includes Japan’s winnable draw against France last November and their spectacular 28-0 win performance against Georgia in June this year.

Scrum Half:

Tanaka: 61%
Nagare: 37%
Uchida: 2%

The third-choice halfback Keisuke Uchida has only played 2% of the available Tier 1 or 2 test match minutes under Joseph, a lower proportion than any other third option. Therefore, there is very little depth under the 9 and 21 jerseys. However, if we analyse these three players based on the number of caps (101 caps between them):

Tanaka: 66% (67 caps)
Nagare: 12% (12 caps)
Uchida: 22% (22 caps)

Uchida has more caps than Nagare despite being the same age (both currently 26). This is mainly because Uchida debuted for Japan at the age of 19 whereas Nagare debuted at the age of 24. Furthermore, Uchida has also gained high-level rugby experience by playing for the Sunwolves in the last two seasons. So through this lens, the Japan side has a reasonable amount of experience spread across the three halfbacks.

Fly Half and Centres:

Rank Game minutes proportion Players
First choice 52% Lafaele and Tamura
Second choice 29% Tatekawa and Tupou
Third choice 10% Carpenter and Ogura

Japan has a lot of versatility across these set of positions. Across these six players, five can play as a centre (all apart from Ogura) and four can play fly half (all apart from Tupou and Carpenter).

Also, the distribution of depth here looks similar to the ideal depth distribution described by Gareth and Steve. Therefore, with a good distribution of game time and versatility, the 10-12-13 channel for Japan is looking strong.

Back Three:

Rank Game minutes proportion Players
First choice 56% Matsushima and Fukuoka
Second choice 29% Noguchi and Yamada
Third choice 10% Lemeki and Lotoahea

The depth distribution here fits Gareth and Steve’s ideal depth distribution even closer. On top of this, we must remember experience playing in high-pressure environments (such as previous World Cups or at the Olympic Games) is also important for success at the World Cup. This is especially important for Japan because they will face a lot of media pressure as the hosts.

In the back three, Matsushima and Yamada were both first-choice starting players at the last World Cup. Furthermore, Fukuoka and Lemeki both played key roles in the Japan Sevens side that reached the Semi-Finals (including a victory over New Zealand in the process) at the Rio Olympic Games. So overall, the depth and also the mental strength of Japan’s back three is shaping well for the World Cup.


Author: Kaito Goto


  1. Brilliant! Now I really have something to dig into! We see so little information about the Japanese team here in Britain. This is fist rate information, Kaito. Thank you so much!

    I notice that you have only listed 12 players for the back six. While I understand that there is a good level of overlap for these positions, surely that makes injury more of a worry as losing one player removes cover for two or more positions?

  2. Thanks for your comment as always Paul. Like what Gareth mentioned once, no matter how much depth is built, the strongest 23 doesn’t change. So to answer your question, I think Jamie Joseph isn’t keen on providing game time outside of these 12 players. It’s an all or nothing bet to make the QF next year I think!

  3. Thanks for this breakdown of options. Excellent piece of work Kaito.
    During the 2017 games v Ireland 2nd row was the real area of obvious weakness for Nippon. As you noted, Luke Thompson, who played at Blackrock College RFC, had to come out of retirement!
    Ireland have some good options in the 2nd row. With 1 exceptional talent in James Ryan. Maybe set piece is where Ireland will target. Although Ireland don’t have a whole pile of depth either!

    • Ahead of Japan’s clash with Ireland tomorrow, this comment sprung to my mind. What a beautiful story for Luke Thompson to start against Ireland for the host nation. May the best team win!

  4. Thanks for your comment C Mc. Interesting how you contrasted Japan with Ireland. Hopefully, Ireland won’t have too many unlucky injuries like the last World Cup. Ireland is an incredibly important team to make next year’s World Cup competitive. How many of Ireland’s locks have retired since the last World Cup apart from the great O’Connell?

    • I’ve green tinted glasses Kaito! Keep up the good work- will look out for more!
      Since the WC Donnacha Ryan is no longer in the squad- he moved from Munster to Racing.
      Grandslam was won on the back of some wonderful work from James Ryan, Henderson & Toner at Lock. Quinn Roux also played against Italy & played a few mins v Wales.
      If 2 of the aforementioned trio got injured I wouldn’t be surprised if D.Ryan was parachuted back in as one of the 3 WC second rows.
      Current Depth Chart: 4.Henderson 5.J.Ryan 19.Toner. Followed by Tadhg Beirne (& 6or8), Roux, Ultan Dillane. Kleyn at Munster will be eligible just before the WC.

      • Thanks for this constructive comment. Will look out for these players during November. Hopefully, Henderson, JRyan and Toner will stay fit for the All Blacks Test at least!

    • Thanks for your comment and great point CMc. Eddie Jones talked about him glowingly during this portion of his last talk in Japan:

      He is a prime example of Japan’s structural problem. Even players like him with world-class potential waste four years playing University rugby. Like what Eddie said in the video, if players like him spend those four years playing in the top league instead, and play against high-quality players across the world and with world-class coaching under coaches like Robbie Deans and Jake White, I believe Yamasawa would’ve fulfilled his potential and had a realistic chance of playing at next years World Cup.

      So this is my thought on Yamasawa, but it’s definitely feasible for him to play in the 2023 World Cup. Thanks for the video, I love it when people share links of decent rugby youtube videos. There’s very few of them outside of The1014 and Gareth Mason channels nowdays.

      • Thanks for the insight Kaito. Had no idea that’s where the young Japanese players developed.
        Also refreshing to listen to Eddie Jones talk sense!

        • In my opinion, that video is easily the best video on youtube to learn about how Japanese rugby is structured. Hope you enjoyed it.

  5. I just re-watched the video C Mc. Interesting how Eddie talked about “colour” of teams in this portion:

    As an Australian, he said the All Blacks are the best team at keeping their colour. All Blacks will always go for a try even if the game is tight and they get a penalty inside the 22. Almost mirrors what happened in Wellington a few weeks ago!

  6. Thanks a lot for sharing Jake White’s article. When coaches are given a freedom of what to say, it creates beautiful journalism, not when some journalist asks a disrespectful unintelligent question tbh.

    Especially like old it when he pointed out that if you’re not keen to share intellectual property, you won’t get a job in nz rugby. That’s what’s missing in Japan as well, there’s very little cohesion between Uni rugby, top league and the national side. They’re almost like three completely different individual entities.

  7. Awesome stuff Kaito! This must have taken you a while? I realise I am late to the party with this, but I don’t get to dedicate as much time to rugby as I would like!! Does anyone??

    This is genuinely a really great read. It really links things up nicely. I actually didn’t know much of the Japan team other than the usual presumptions and what is in mainstream media. As said by Paul, there’s not a great deal of detail about Japan that hasn’t been generated by the RWC. But this really highlights their position in the world of rugby. As a Scotsman I would bracket Japan and Scotland as fairly similar on the face of things.

    It do feel it’s good time to point out how big an achievement it is for anyone to still have both feet still in the national side aged 38. Especially when we consider how many youngsters are having their playing careers cut short due to injuries! Luke Thompson is not alone and I wonder (perhaps disrespectfully) if this serves to highlight the lack of depth for some nations.

    When you look at some players who have been or are similar positions – Easton Roy is the most obvious to me ( https://www.scotsman.com/news/world-s-oldest-rugby-player-still-going-strong-at-95-1-4732582 )…Well maybe a better example is the iconic Sergio Parisse – This creates for some controversial discussions around depth. The most common phrase I’ve heard in Scotland is ‘If he was in any other Tier 1 nation, he would’t be 2nd choice’. I don’t share that sentiment, but still I can certainly see the argument for.

    I do like the statistic side of rugby though. Sometimes they seem to form a discernible pattern that equates to results and sometimes they don’t. I always look back on the film Moneyball with an eye on rugby and wonder if a similar mindset would change the game. Maybe not quite as effective with very differing game limitations, but an interesting concept to me all the same.

    Any way thank you for stimulating my brain into a rugby related frenzy!!!


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