diff --git a/go/buscalls/seatchunks.go b/go/buscalls/seatchunks.go
new file mode 100644
index 00000000..94a2648c
--- /dev/null
+++ b/go/buscalls/seatchunks.go
@@ -0,0 +1,87 @@
+package buscalls
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+	"time"
+)
+
+// SeatChunks is the send of one seat verb's answer file in chunks (design 47 G §681, A-64, A-139), a verb whose seat
+// definition says `chunks: true`: the holder's process sends the nth chunk on mesh.seat.<seat>.chunk.<verb>.<call>.<n>,
+// and the caller acknowledges it on mesh.seat.<seat>.ack.<verb>.<call>.<n> within SeatAckWithin before the next is sent.
+// `call` is the 128 random bits the caller chose. The holder sends with it and the caller receives with it: one form.
+type SeatChunks struct {
+	Seat, Verb, Call string
+}
+
+// SeatChunkBytes is at most what one chunk carries: 512 KiB.
+const SeatChunkBytes = 512 << 10
+
+// SeatAckWithin is how long the holder waits for a chunk's acknowledgement, and so how long a caller waits for the next chunk.
+const SeatAckWithin = 30 * time.Second
+
+// SeatChunk is the body of one chunk: its number from 1, how many there are, and its bytes.
+type SeatChunk struct {
+	N    int64  `json:"n"`
+	Of   int64  `json:"of"`
+	Data []byte `json:"data"`
+}
+
+// Chunk is the subject of the nth chunk.
+func (c SeatChunks) Chunk(n int64) string {
+	return "mesh.seat." + c.Seat + ".chunk." + c.Verb + "." + c.Call + "." + strconv.FormatInt(n, 10)
+}
+
+// Ack is the subject the nth chunk is acknowledged on.
+func (c SeatChunks) Ack(n int64) string {
+	return "mesh.seat." + c.Seat + ".ack." + c.Verb + "." + c.Call + "." + strconv.FormatInt(n, 10)
+}
+
+// Chunks is every chunk subject of this call: what a caller subscribes to before it asks the verb.
+func (c SeatChunks) Chunks() string {
+	return "mesh.seat." + c.Seat + ".chunk." + c.Verb + "." + c.Call + ".*"
+}
+
+// SeatAcks is every acknowledgement of a verb's sends: what the holder subscribes to.
+func SeatAcks(seat, verb string) string {
+	return "mesh.seat." + seat + ".ack." + verb + ".*.*"
+}
+
+// ErrSeatChunkMissed is a chunk that did not come within its bound: the holder ended the send.
+var ErrSeatChunkMissed = errors.New("a chunk did not come within its bound, so the send ended")
+
+// Receive reads `of` chunks in order, writes each one's bytes to w and acknowledges it before the next is sent. next
+// yields the subject and body of the next chunk heard on Chunks(), or ErrSeatChunkMissed at its bound (SeatAckWithin);
+// ack publishes on a subject. A chunk out of order, of another count or on another subject ends the receive, and so the
+// send, since it is never acknowledged. It answers the bytes written.
+func (c SeatChunks) Receive(of int64, next func() (subject string, body []byte, err error), ack func(subject string) error, w io.Writer) (int64, error) {
+	var written int64
+	for n := int64(1); n <= of; n++ {
+		subject, body, err := next()
+		if err != nil {
+			return written, fmt.Errorf("chunk %d of %d: %w", n, of, err)
+		}
+		if subject != c.Chunk(n) {
+			return written, fmt.Errorf("chunk %d of %d came on %s, not %s", n, of, subject, c.Chunk(n))
+		}
+		var ch SeatChunk
+		if err := json.Unmarshal(body, &ch); err != nil {
+			return written, fmt.Errorf("chunk %d of %d does not read: %w", n, of, err)
+		}
+		if ch.N != n || ch.Of != of {
+			return written, fmt.Errorf("chunk %d of %d says it is %d of %d", n, of, ch.N, ch.Of)
+		}
+		k, err := w.Write(ch.Data)
+		written += int64(k)
+		if err != nil {
+			return written, fmt.Errorf("chunk %d of %d cannot be written: %w", n, of, err)
+		}
+		if err := ack(c.Ack(n)); err != nil {
+			return written, fmt.Errorf("chunk %d of %d cannot be acknowledged: %w", n, of, err)
+		}
+	}
+	return written, nil
+}
diff --git a/go/buscalls/seatchunks_test.go b/go/buscalls/seatchunks_test.go
new file mode 100644
index 00000000..4b1a995c
--- /dev/null
+++ b/go/buscalls/seatchunks_test.go
@@ -0,0 +1,72 @@
+package buscalls
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"strings"
+	"testing"
+)
+
+// TestSeatChunksReceive: the chunks of a send are written in order and each acknowledged before the next; a missed,
+// misplaced or miscounted chunk ends the receive unacknowledged (design 47 G §681, A-139).
+func TestSeatChunksReceive(t *testing.T) {
+	c := SeatChunks{Seat: "mesh-broker", Verb: "snapshot-get", Call: "0123456789abcdef0123456789abcdef"}
+	if c.Chunk(2) != "mesh.seat.mesh-broker.chunk.snapshot-get.0123456789abcdef0123456789abcdef.2" ||
+		c.Ack(2) != "mesh.seat.mesh-broker.ack.snapshot-get.0123456789abcdef0123456789abcdef.2" ||
+		c.Chunks() != "mesh.seat.mesh-broker.chunk.snapshot-get.0123456789abcdef0123456789abcdef.*" ||
+		SeatAcks("mesh-broker", "snapshot-get") != "mesh.seat.mesh-broker.ack.snapshot-get.*.*" {
+		t.Fatalf("subjects: %s %s %s", c.Chunk(2), c.Ack(2), c.Chunks())
+	}
+	type sent struct {
+		subject string
+		body    SeatChunk
+		missed  bool
+	}
+	good := []sent{{subject: c.Chunk(1), body: SeatChunk{N: 1, Of: 3, Data: []byte("ab")}},
+		{subject: c.Chunk(2), body: SeatChunk{N: 2, Of: 3, Data: []byte("cd")}},
+		{subject: c.Chunk(3), body: SeatChunk{N: 3, Of: 3, Data: []byte("e")}}}
+	for _, tc := range []struct {
+		name  string
+		sends []sent
+		want  string
+		acks  int
+		err   string
+	}{
+		{name: "three chunks", sends: good, want: "abcde", acks: 3},
+		{name: "a missed chunk", sends: append(good[:1:1], sent{missed: true}), want: "ab", acks: 1, err: "chunk 2 of 3"},
+		{name: "out of order", sends: []sent{good[1]}, acks: 0, err: "came on"},
+		{name: "another count", sends: []sent{{subject: c.Chunk(1), body: SeatChunk{N: 1, Of: 2, Data: []byte("x")}}}, err: "says it is 1 of 2"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			i, acks := 0, 0
+			next := func() (string, []byte, error) {
+				if i >= len(tc.sends) || tc.sends[i].missed {
+					return "", nil, ErrSeatChunkMissed
+				}
+				s := tc.sends[i]
+				i++
+				body, _ := json.Marshal(s.body)
+				return s.subject, body, nil
+			}
+			ack := func(subject string) error {
+				acks++
+				if subject != c.Ack(int64(acks)) {
+					t.Fatalf("ack %d on %s", acks, subject)
+				}
+				return nil
+			}
+			var out bytes.Buffer
+			n, err := c.Receive(3, next, ack, &out)
+			if tc.err == "" && err != nil || tc.err != "" && (err == nil || !strings.Contains(err.Error(), tc.err)) {
+				t.Fatalf("err %v, want %q", err, tc.err)
+			}
+			if tc.name == "a missed chunk" && !errors.Is(err, ErrSeatChunkMissed) {
+				t.Fatalf("a missed chunk is not ErrSeatChunkMissed: %v", err)
+			}
+			if out.String() != tc.want || n != int64(len(tc.want)) || acks != tc.acks {
+				t.Fatalf("wrote %q (%d), %d acks; want %q, %d acks", out.String(), n, acks, tc.want, tc.acks)
+			}
+		})
+	}
+}
diff --git a/go/bussnap/restore.go b/go/bussnap/restore.go
new file mode 100644
index 00000000..ee70e73f
--- /dev/null
+++ b/go/bussnap/restore.go
@@ -0,0 +1,158 @@
+package bussnap
+
+import (
+	"archive/tar"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/busarchive"
+
+	"github.com/nats-io/nats.go"
+)
+
+// The keeper's restore in place of a snapshot it took (design 47 G §681): each stream of the file put back under its own
+// name, only where no stream of that name is live.
+
+// APIStreamDelete is the subject the keeper removes its own partial stream with.
+const APIStreamDelete = "$JS.API.STREAM.DELETE."
+
+const restoreChunk = 64 * 1024
+
+// ManifestOf reads the manifest of a snapshot file: the streams it holds, without unpacking them.
+func ManifestOf(path string) (*busarchive.Manifest, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	tr := tar.NewReader(f)
+	hdr, err := tr.Next()
+	if err != nil {
+		return nil, fmt.Errorf("the snapshot does not read: %w", err)
+	}
+	if hdr.Name != busarchive.ManifestName {
+		return nil, fmt.Errorf("the snapshot starts with %q, not its manifest", hdr.Name)
+	}
+	raw, err := io.ReadAll(io.LimitReader(tr, 64<<20))
+	if err != nil {
+		return nil, err
+	}
+	var m busarchive.Manifest
+	if err := json.Unmarshal(raw, &m); err != nil {
+		return nil, fmt.Errorf("its manifest: %w", err)
+	}
+	return &m, nil
+}
+
+// Live says whether a stream of that name exists.
+func Live(ctx context.Context, nc *nats.Conn, name string) (bool, error) {
+	err := Request(ctx, nc, APIStreamInfo+name, nil, nil)
+	var api *APIError
+	switch {
+	case err == nil:
+		return true, nil
+	case errors.As(err, &api) && api.Code == 404:
+		return false, nil
+	}
+	return false, err
+}
+
+// DeleteStream removes a stream; one that is not there is no error.
+func DeleteStream(ctx context.Context, nc *nats.Conn, name string) error {
+	err := Request(ctx, nc, APIStreamDelete+name, nil, nil)
+	var api *APIError
+	if errors.As(err, &api) && api.Code == 404 {
+		return nil
+	}
+	return err
+}
+
+// RestoreFile puts every stream of the snapshot file back under its own name, each sent in chunks the server answers; it
+// ends with the context's bound. A stream already there is the caller's to have refused beforehand.
+func RestoreFile(ctx context.Context, nc *nats.Conn, path, scratch string, log func(string, ...any)) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	a, err := busarchive.ReadArchive(f, scratch)
+	if err != nil {
+		return err
+	}
+	defer a.Close()
+	if err := a.Verify(); err != nil {
+		return err
+	}
+	for _, s := range a.Manifest.Streams {
+		started := time.Now()
+		if err := restoreStream(ctx, nc, a, s); err != nil {
+			return fmt.Errorf("stream %s: %w", s.Name, err)
+		}
+		log("%s: restored in %.2fs", s.Name, time.Since(started).Seconds())
+	}
+	return nil
+}
+
+func restoreStream(ctx context.Context, nc *nats.Conn, a *busarchive.Archive, s busarchive.StreamEntry) error {
+	meta, archive, err := a.Open(s)
+	if err != nil {
+		return err
+	}
+	defer archive.Close()
+	var req map[string]json.RawMessage
+	if err := json.Unmarshal(meta, &req); err != nil || req["config"] == nil {
+		return errors.New("its meta is not a stream's configuration and state")
+	}
+	var resp struct {
+		DeliverSubject string `json:"deliver_subject"`
+	}
+	if err := Request(ctx, nc, APIStreamRestore+s.Name, req, &resp); err != nil {
+		return err
+	}
+	if resp.DeliverSubject == "" {
+		return errors.New("the server gave nowhere to send the archive")
+	}
+	buf := make([]byte, restoreChunk)
+	for {
+		n, err := archive.Read(buf)
+		if n > 0 {
+			reply, rerr := nc.RequestWithContext(ctx, resp.DeliverSubject, buf[:n])
+			if rerr != nil {
+				return fmt.Errorf("sending the archive: %w", rerr)
+			}
+			if len(reply.Data) > 0 {
+				return fmt.Errorf("the server refused the archive: %s", Truncate(reply.Data))
+			}
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+	}
+	final, err := nc.RequestWithContext(ctx, resp.DeliverSubject, nil)
+	if err != nil {
+		return fmt.Errorf("finishing the restore: %w", err)
+	}
+	var created struct {
+		Error *APIError   `json:"error"`
+		State StreamState `json:"state"`
+	}
+	if err := json.Unmarshal(final.Data, &created); err != nil {
+		return fmt.Errorf("the server's last answer is not JSON: %q", Truncate(final.Data))
+	}
+	if created.Error != nil {
+		return created.Error
+	}
+	if created.State.LastSeq < s.LastSeq || (s.Messages > 0 && created.State.Messages == 0) {
+		return fmt.Errorf("restored with %d message(s) up to sequence %d; the snapshot held %d up to %d",
+			created.State.Messages, created.State.LastSeq, s.Messages, s.LastSeq)
+	}
+	return nil
+}
diff --git a/go/bussnap/restore_integration_test.go b/go/bussnap/restore_integration_test.go
new file mode 100644
index 00000000..e73c83e4
--- /dev/null
+++ b/go/bussnap/restore_integration_test.go
@@ -0,0 +1,63 @@
+//go:build integration
+
+package bussnap_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/bussnap"
+	"git.novox.be/novox/mesh-sdk/go/testbus"
+
+	"github.com/nats-io/nats.go"
+)
+
+// TestOneStreamIsTakenRemovedAndRestored: the take and restore of one stream is mesh-sdk's (design 47 G §655, A-125):
+// a stream's snapshot taken with Into, the stream deleted, and RestoreFile puts it back under its own name with its
+// messages; a second restore over the live name is refused by the server.
+func TestOneStreamIsTakenRemovedAndRestored(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	nc, err := nats.Connect(testbus.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	js, err := nc.JetStream()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.AddStream(&nats.StreamConfig{Name: "KEPT_one", Subjects: []string{"kept.one.>"}}); err != nil {
+		t.Fatal(err)
+	}
+	for _, m := range []string{"a", "b", "c"} {
+		if _, err := js.Publish("kept.one."+m, []byte(m)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	file, err := bussnap.Into(nc, t.TempDir())(ctx, []string{"KEPT_one"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	m, err := bussnap.ManifestOf(file)
+	if err != nil || len(m.Streams) != 1 || m.Streams[0].Name != "KEPT_one" {
+		t.Fatalf("the manifest says %+v, %v; want the one stream KEPT_one", m, err)
+	}
+	if err := bussnap.DeleteStream(ctx, nc, "KEPT_one"); err != nil {
+		t.Fatal(err)
+	}
+	if live, err := bussnap.Live(ctx, nc, "KEPT_one"); err != nil || live {
+		t.Fatalf("live after its deletion: %v, %v", live, err)
+	}
+	if err := bussnap.RestoreFile(ctx, nc, file, t.TempDir(), t.Logf); err != nil {
+		t.Fatal(err)
+	}
+	info, err := js.StreamInfo("KEPT_one")
+	if err != nil || info.State.Msgs != 3 || info.State.LastSeq != 3 {
+		t.Fatalf("restored as %+v, %v; want 3 messages up to sequence 3", info, err)
+	}
+	if err := bussnap.RestoreFile(ctx, nc, file, t.TempDir(), t.Logf); err == nil {
+		t.Fatal("a restore over the live name was taken")
+	}
+}
diff --git a/go/bussnap/snapshot.go b/go/bussnap/snapshot.go
index c2b285ea..24231603 100644
--- a/go/bussnap/snapshot.go
+++ b/go/bussnap/snapshot.go
@@ -415,7 +415,7 @@ func Into(nc *nats.Conn, dir string) func(ctx context.Context, streams []string)
 		if dir == "" {
 			return "", errors.New("no snapshots directory is set (MESH_NATS_SNAPSHOTS_DIR), so no snapshot is taken and nothing is removed")
 		}
-		name := filepath.Join(dir, "entry-"+strings.Join(streams, "+")+"-"+time.Now().UTC().Format("20060102T150405Z")+".tar")
+		name := filepath.Join(dir, "entry-"+strings.Join(streams, "+")+"-"+time.Now().UTC().Format("20060102T150405.000000Z")+".tar")
 		f, err := os.CreateTemp(dir, ".entry-*.partial")
 		if err != nil {
 			return "", err