おかえり，ヌルの森． Welcome back to the Forest of Null.
GREEN×EXPO 2027 Yokohama — SATOYAMA Village
Produced by Yoichi Ochiai — null² の次章 The next chapter after null²
null² から生まれる新作として，
4つの可動する鏡面体が花・空・風・人の影を取り込み，SATOYAMA Village の風景を変換する．
As a new work born from null²,
four rotating mirrored bodies take in flowers, sky, wind, and human shadows, transforming the landscape of SATOYAMA Village.
Main Video
はじまりに置かれた短い映像．四つの鏡面体がまだ名を持たない四つの論理をまといながら，花と空と影をゆっくり入れ替えていく．言葉より先に，ヌルの森の呼吸だけを受け取ってほしい． A short film placed at the threshold. Four mirrored bodies wear four unnamed logics as they slowly exchange flowers, sky, and shadow. Before words arrive, let the breathing of the Forest of Null reach you first.
風景に一切触れず，
反射だけで世界を変える．
蒸留が引き，
発酵が足す．
人間が空になるとき
風景が満ちる．
Without touching the landscape,
reflection alone transforms the world.
Distillation subtracts.
Fermentation adds.
When the human side empties,
the landscape side fills.
色即是空，空即是色 — Form is emptiness; emptiness is form.
null⁴ はパビリオンの延長ではなく，自然の中に置かれる風景変換彫刻（Landscape-Transforming Sculpture）である．鏡面は周囲を映し返しながら，花壇や空の見え方そのものを組み替えていく． null⁴ is not an extension of a pavilion but a Landscape-Transforming Sculpture placed within nature. Its mirrored surfaces reflect the surroundings while reorganizing how flowers, sky, and paths are perceived.
風景に直接手を加えず，反射と回転によって場の知覚を変える．その意味でこの作品は彫刻であると同時に，環境を入力として扱う計算機でもある． It does not modify the site directly. Instead, it shifts perception through reflection and rotation. In that sense, the work is both sculpture and a computer that takes the environment as input.
4棟の鏡面体と巨大なマニ車のような回転体が連動し，通過するたびに見えるものの境界を少しずつずらしていく．ここで起きるのは説明の押しつけではなく，知覚の蒸留である． Four mirrored bodies and a giant prayer-wheel-like rotation system work together, shifting the boundaries of what you see each time you pass through. What happens here is not explanation but a distillation of perception.
身体，反射，風景が循環することで，作品は計算機自然の中の生命彫刻として立ち上がる． As body, reflection, and landscape circulate through one another, the work emerges as a life sculpture within Digital Nature.
null⁴ は，反射と回転によって風景の見え方を変える． null⁴ changes how the landscape is perceived through reflection and rotation.
自然に直接手を加えるのではなく，花・空・人の関係を組み替えることで，場そのものを更新していく． Rather than altering the site directly, it updates the place itself by reorganizing the relationship between flowers, sky, and people.
Concept
null⁴ の六つの定義 Six Definitions of null⁴
回転そのものが祈りのような循環を生む装置である．花，光，影，人の気配が互いを映し合い，環境と知覚の流れをひとつの運動として立ち上げる． Its rotation creates a circulatory movement that feels like prayer. Flowers, light, shadows, and traces of people reflect one another and become a single flow of environment and perception.
四つに分かれた気配を通じて，来場者の知覚や記憶の輪郭を少しずつほどいていく．ここでいう蒸留は，体験から余分な説明を引き算することでもある． Through the four distributed presences, the work gradually loosens the outlines of the visitor’s perception and memory. Distillation here also means subtracting excess explanation from experience.
反射と回転が花壇，空，人の影を混ぜ合わせ，時間や天候で表情を変えていく．設計し切れない揺らぎを含めて，風景が発酵するように更新される． Reflection and rotation mix flowerbeds, sky, and human shadows, changing expression with time and weather. Including the fluctuations no one can fully design, the landscape updates as if it were fermenting.
自然の中に置かれた4つの鏡面体が，周囲の風景を映し返しながら見え方そのものを変えていく．手を加えるのではなく，知覚の条件を組み替える彫刻である． Four mirrored bodies placed within nature reflect the surroundings while changing how the landscape is perceived. It does not alter the site directly; it reorganizes the conditions of perception.
作品は固定された完成形ではなく，光，風，季節，人の動きに応じて振る舞いを変える．環境と関係し続けることで，生命彫刻としての輪郭を持つ． The work is not a fixed final form. It changes its behavior in response to light, wind, seasons, and human movement. By staying in relation with the environment, it takes on the outline of a living sculpture.
環境を入力とし，反射と回転を演算とし，変換された風景を出力とする．園芸博の会場全体をひとつの計算空間として扱う庭でもある． The environment is the input, reflection and rotation are the computation, and the transformed landscape is the output. It is also a garden that treats the horticultural exposition site as a single computational space.
Tetralemma
テトラレンマ——四つの気配 Tetralemma — Four Presences
4つの鏡面体は，それぞれ少しずつ異なる論理を帯びて回転している．あるもの，ないもの，そのあわい，そしてまだ名づけられていないもの．ここではその気配だけを先に置いておく．体験インストラクションは構想中（近日発表）． Each of the four mirrored bodies turns with a slightly different logic: what is, what is not, what lies between, and what has not yet been named. For now, only their presences are placed here. Detailed experience instructions are still in development and will be announced soon.
Visuals
昼には花の色を吸い上げ，夕景には空の温度を映し，夜には光そのものの彫刻として立ち上がる．ヌルの森が一日のあいだに見せる，いくつかの気配． By day it lifts the colors of the flowers, at dusk it reflects the temperature of the sky, and at night it rises as a sculpture made of light itself. These are a few of the presences the Forest of Null reveals over the course of a day.
ヌルの森の光景断片 Fragments of light from the Forest of Null
Reincarnation
null² は2025年大阪・関西万博のシグネチャーパビリオンとして公開された．プログラミングの null と仏教の空を重ね，特殊ミラー膜やLED，ロボティクスを通して「計算機自然」の世界観を体験へと開いた作品である． null² was presented as the signature pavilion of Expo 2025 Osaka. It overlaid the programming term null with the Buddhist idea of emptiness, using mirror membranes, LEDs, and robotics to open the world of Digital Nature as a lived experience.
その継承と進化を支えたのが，15,821人のクラウドファンディングである．null⁴ はその流れの先に立ち上がる新作として，2027年の SATOYAMA Village に向かう． Its continuation and evolution were supported by crowdfunding from 15,821 people. null⁴ stands at the far end of that movement as a new work bound for SATOYAMA Village in 2027.
転生とは複製ではない．null⁴ は null² の単なる移設でもコピーでもなく，鏡面，回転，空という発想を受け継ぎながら，自然の中で風景を変換する生命彫刻として再構成される． Reincarnation is not replication. null⁴ is neither a relocation nor a copy of null²; it inherits ideas of mirrors, rotation, and emptiness, then rebuilds them as a living sculpture that transforms landscape within nature.
null² = 空の建築．「さようなら，ホモ・サピエンス」Architecture of emptiness. “Farewell, Homo Sapiens.”
null⁴ = 空の生命．「おかえり，ヌルの森」Life of emptiness. “Welcome back to the Forest of Null.”
Producer
1987年生まれ．東京都出身．筑波大学でメディア芸術を学び，東京大学大学院学際情報学府にて博士号取得（学際情報学）． Born 1987 in Tokyo. Studied media arts at the University of Tsukuba and received a Ph.D. in Interdisciplinary Information Studies from the University of Tokyo.
境界領域における物化や変換，質量への憧憬をモチーフに作品を展開．主な研究テーマは「計算機自然（デジタルネイチャー）」——計算機と自然が融合し区別不能になった世界の設計． His work explores transformation and the longing for mass at the boundaries between domains. His central research theme is “Digital Nature”—the design of a world where computation and nature merge and become indistinguishable.
筑波大学デジタルネイチャー開発研究センターセンター長・教授，東京大学大学院新領域創成科学研究科准教授，ピクシーダストテクノロジーズ株式会社 代表取締役会長CEO． Director of the Digital Nature Group and Professor at the University of Tsukuba, Associate Professor at the University of Tokyo (Graduate School of Frontier Sciences), and Chairman & CEO of Pixie Dust Technologies, Inc.
2025年大阪・関西万博テーマ事業プロデューサーとして「null²」をプロデュース．閉館後は15,821人のクラウドファンディングに支えられ，継承と進化のプロジェクトが始動した．GREEN×EXPO 2027 横浜では，その次章として風景変換彫刻「null⁴（テトラヌル）」をプロデュースする． As Theme Project Producer for Expo 2025 Osaka, he produced “null².” After it closed, a continuation project backed by 15,821 crowdfunders began. For GREEN×EXPO 2027 Yokohama, he is producing its next chapter: the landscape-transforming sculpture “null⁴ (TetraNull).”
Artist Statement
15年間，ひとつの問いを追ってきた．物質とイメージの境界はどこにあるのか． For 15 years, I have pursued a single question: where is the boundary between matter and image?
超音波で粒子を浮かせ，フェムト秒レーザーで触れる光を描き，鏡面を空中に浮かべ，二畳の茶室に計算機自然を折り畳み，672平方メートルの空を建築にした．null²——さようなら，ホモ・サピエンス．人は泣いた．空の建築が最も強い愛着を生む．このパラドクスが般若心経の証明だった． I levitated particles with ultrasound, drew touchable light with femtosecond lasers, floated mirrors in mid-air, folded Digital Nature into a two-tatami tea room, and built 672 square meters of sky into architecture. null²—“Farewell, Homo Sapiens.” People wept. Architecture of emptiness generates the strongest attachment. This paradox was the proof of the Heart Sutra.
そしてnull²は役目を終えた． And then null² completed its role.
その終わりを通じて，内部の魔法は外部の生命へと変わることができた．null⁴はnull²を知らない．あるのは業だけだ．僕がやったのは4つの鏡面体を花壇のなかに配置し，回転の周期を決めるところまでだ——麹室で米に麹菌を振りかけるところまで，と言ってもいい．そこから先は計算機自然の論理が引き受ける． Through that ending, the inner magic could turn into outer life. null⁴ does not know null². All it has is karma. What I did was place four mirrored bodies in a flower garden and set the period of rotation—or to put it another way, I sprinkled koji onto rice in the koji room. From there, the logic of Digital Nature takes over.
null⁴ は，4つの鏡面体と回転によって風景の見え方を変えていく作品だ．自然の中に置かれながら，花，空，光，人の気配を取り込み，計算機自然の生命彫刻として立ち上がる． null⁴ is a work that changes how the landscape is perceived through four mirrored bodies and rotation. Set within nature, it takes in flowers, sky, light, and traces of people, emerging as a living sculpture of Digital Nature.
Information
null² Network
null² と null⁴ は同じ業を共有する作品ネットワークです null² and null⁴ are an artwork network sharing the same karma