What the Laws Left Open: Provisions Adopted in Kimwipe Table Tennis Practice, 2016–2026

Introduction

The Laws of Kimwipe table tennis published in the first issue of this journal (Iwatsuki, 2016) were a framework rather than a rulebook. They fixed what seemed distinctive about the sport — the instrument, the playing surface, a condition on the ball — and left the rest to be worked out, ending with the statement that methods for evaluating players “still remain to be discussed”. That was consistent with the founding Preface, which held that rules for a scientific sport should arise from the consent of the community that plays it rather than from the association (International Kimwipe Table Tennis Association, 2016).

Ten years on, the sport has been played regularly at a number of universities and schools, and each occasion has had to supply, in practice, the provisions the Laws left open. This review collects those provisions from the sources available, sets them against the Laws, and states where each open point now stands.

The Laws under review are my own, and I edit the journal in which this appears; the reader should weigh the conclusions accordingly.

What the Laws left open

The Laws specify the racket (a Kimwipes box, with nothing attached), the playing surface (any horizontal, roughly rectangular table, with an explicit centre line and no requirement for a net), and a condition on the ball (a restitution coefficient above $2^{-\frac{1}{2}}$). For seated play they limit the table height to $7.6\times {10}^{-1}$ m.

They do not specify a service, the conditions under which a point is won or lost, the length of a game or a match, what happens at a tie, the dimensions of the court, or the order of play. On the determination of a winner they give a principle — statistical validity rather than a fixed target score — and explicitly defer the method. These seven points are the ones a group has to settle for itself before it can hold a game, and they are the points this review follows.

What was adopted, source by source

A word on sources first. The association was founded in 2008 and the University of Tokyo club in 2012, four years before this journal; play there, and at the meetings the association itself has held, goes back well before any of it was written down. This review is confined to what was set down in writing and can be cited, and that record begins only in 2018. The years attached to the headings below are therefore the years in which a practice was first described, not the years in which it began. A reader who knows the sport from the inside will recognise much of what follows as older than its citation.

Bench play, as described in 2018

The earliest written account this review could reach is in the Keio student press, reporting on a club founded there in June 2018 and on the sport as it was by then established among universities in Tokyo, with the East Tokyo Kimwipe Table Tennis Club named as a pioneer (慶應塾生新聞会, 2018). The racket is a Kimwipes box and so is the net; the court is any convenient desk. The stated object is to sustain a rally and to talk while doing so. Nothing is said about scoring, because nothing is scored.

Festival play, as described in 2018

At the University of Tokyo's Komaba Festival in November 2018 the game was played on the gymnasium's table tennis tables, with Kimwipes boxes for rackets and boxes again for the net, a hundred boxes being used over the event. The rules were described as the same as those of table tennis (東京大学新聞社, 2018). The report notes the essential adaptation — a ball that barely bounces — and a tactic that had already emerged from it, dropping the ball short near the net where a box held at arm's length cannot easily reach.

Championship requirements, written in 2023

For the first All-Japan championship the University of Tokyo club published a written set of requirements (東京大学キムワイプ卓球会, 2023a). The racket is a Kimwipe or a KimDry — the wiper itself rather than the box, and a second brand admitted. The net is Kimwipes, KimDry, or something equivalent. A game is played to eleven points, a match is the first to two games, deuce applies, and the draw is single-elimination. Everything else is the same as table tennis. Twelve players competed under these rules (東京大学キムワイプ卓球会, 2023b).

Where each open point stands

Racket. The box held for at least seven years and was the one provision every source shared with the Laws. The 2023 requirements move to the wiper itself and admit a second brand. No source explains the change; it is the first question a future contributor might usefully answer.

Net. The Laws' position that no net is needed has not been followed by any group. Every source uses an improvised net, first a box, later the wiper. The reason is probably the one the festival report gives in passing: with a ball that barely bounces, the short game near the net is where the sport is decided, and a physical net is what makes that game legible.

Court. Practice has moved from any available desk to regulation tables when they can be had, and is silent on the point in competition. The Laws' condition on table height for seated play does not appear in any later source.

Scoring, match length, tie. Where play is scored at all, it has been scored as table tennis is: eleven points, deuce, and a best-of-three match in competition. No source proposes anything else. The Laws' preference for a statistically grounded decision over a fixed target has not been taken up, and no source argues against it either; it has simply not been reached.

Service, faults, order of play. Every source that scores the game takes these from table tennis without comment.

Determination of the winner. This is the point the Laws explicitly deferred, and it remains deferred. In competition it is settled by the bracket. As a question about the sport — how many rallies are needed to say with confidence that one player is stronger — it has not been addressed in any source.

Object of play. The one thing that has changed more than any rule. In 2018 the object was to keep the ball going and to talk; by 2023 it was to win. Both forms continue. No source treats them as competing, and it may be that they are simply two sports sharing an instrument.

Conclusion

Of the seven points the Laws left open, four — service, faults, order of play, and the scoring of a game and match — have been settled in practice by taking them from table tennis, without argument and without dissent. Two — the net and the court — have been settled by practice in a direction the Laws did not anticipate. One — how the stronger player is to be identified — remains exactly where the Laws left it.

None of these settlements has been argued for in print. Each is a working answer adopted because a game had to be held, and each is therefore an experiment whose result has been recorded only as the fact of its adoption. The rules of the sport remain, properly, in the experimental stage; what has changed in ten years is that there are now enough experiments, at enough institutions, for the arguments to be made. This journal invites them.

References

1. International Kimwipe Table Tennis Association. (2016). Preface. Scientific Sports, 1(1). https://journal.iktta.org/articles/1/1/1-1-0-abstract.html
2. Iwatsuki, K. (2016). Laws of Kimwipe table tennis. Scientific Sports, 1(1), 1–4. https://journal.iktta.org/articles/1/1/1-1-1-abstract.html
3. 慶應塾生新聞会 [Keio Jukushin Press]. (2018, October 2). 真面目に不真面目の精神とは　キムワイプ卓球を知ろう [The spirit of being seriously unserious: getting to know Kimwipe table tennis]. https://www.jukushin.com/archives/33649
4. 東京大学新聞社 [Todai Shimbun]. (2018, November 21). 【駒場祭おすすめ企画】東京大学キムワイプ卓球会　実験道具でまさかのスポーツ [Komaba Festival recommendation: the University of Tokyo Kimwipe Table Tennis Club, an unlikely sport played with laboratory equipment]. https://www.todaishimbun.org/komabafes_kimwipe20181121/
5. 東京大学キムワイプ卓球会 [University of Tokyo Kimwipe Table Tennis Club]. (2023a, November 16). 【告知】第一回全日本キムワイプ卓球選手権大会要項の公開について [Publication of the requirements for the first All-Japan Kimwipe Table Tennis Championship]. https://ut.tokyo.jp.iktta.org/?p=256
6. 東京大学キムワイプ卓球会. (2023b, November 27). 第一回全日本キムワイプ卓球選手権大会の結果発表 [Results of the first All-Japan Kimwipe Table Tennis Championship]. https://ut.tokyo.jp.iktta.org/?p=266
7. 東京大学キムワイプ卓球会. (2023c, November 27). 第7回キムワイプ卓球会の終了報告 [Report on the conclusion of the 7th Kimwipe table tennis meeting]. https://ut.tokyo.jp.iktta.org/?p=268